Hybrid CD metrology concept compatible with high-volume manufacturing

Abstract

The measurement uncertainty is becoming one of the major components that have to be controlled in order to guarantee sufficient production yield. Already at the R&D level, we have to cope up with the accurate measurements of sub-40nm dense trenches and contact holes coming from 193 immersion lithography or EBeam lithography. Current production CD metrology techniques such as CD-SEM and OCD are limited in relative accuracy for various reasons (i.e electron proximity effect, outputs parameters correlation, stack influence, electron interaction with materials…). Therefore, time for R&D is increasing, process windows degrade and finally production yield can decrease because you can not manufactured correctly if you are unable to measure correctly. A new high volume manufacturing (HVM) CD metrology solution has to be found in order to improve the relative accuracy of production environment otherwise current CD Metrology solution will very soon get out of steam. In this paper, we will present a potential Hybrid CD metrology solution that smartly tuned 3D-AFM and CD-SEM data in order to add accuracy both in R&D and production. The final goal for "chip makers" is to improve yield and save R&D and production costs through real-time feedback loop implement on CD metrology routines. Such solution can be implemented and extended to any kind of CD metrology solution. In a 2 nd part we will discuss and present results regarding a new AFM3D probes breakthrough with the introduction of full carbon tips made will E-Beam Deposition process. The goal is to overcome the current limitations of conventional flared silicon tips which are definitely not suitable for sub-32nm nodes production.

Advances in the atomic force microscopy for critical dimension metrology

“…In HM, two or more instruments are used to measure the same sample (or the features) and the measured data is used synergistically to improve over all measurement accuracy and performance. The tools are not physically integrated, but they are virtually connected to share and combine data through dedicated software, more details about different architectures of the HM are given elsewhere [233][234][235]. High speed, low cost and accurate inline CD metrology of the rapidly shrinking ICs for high volume manufacturing can be met by hybrid metrology (HM) and CD-AFM is considered an important candidate in HM.…”

Model-aided hybrid metrology for surface roughness measurement fusing AFM and SEM data

“…A similar situation has been encountered in other areas of dimensional nano-metrology and especially in the CD metrology of semiconductor structures, where recently the idea of holistic or hybrid metrology has been proposed and elaborated [13][14]. According to it, the results of two or more measuring methods are combined in a synergetic manner to exploit the merits of each method and minimize the impact of their limitations.…”

Optimizing hybrid metrology: rigorous implementation of Bayesian and combined regression

“…Since the term hybrid metrology has gained increased significance in the dimensional metrology community outside NIST [5–7] we will start this work with a short overview of two of the most common techniques in Section 2, namely the Bayesian approach and combined regression. The measured targets and the generalized parameter sets that describe them are discussed in Section 3 before we give a detailed description of the performed error analysis both for OCD and SEM in Section 4 and their impact on the hybridization in Section 5.…”