Process Optimization Using OPE-Master and CDU Master

Abstract

OPE matching and CD-Uniformity control have become inevitable steps for most of high volume manufacturing(HVM) of a state-of-the-art devices. OPE matching is a step to match CDs of various patterns from different scanners or steppers. CD-Uniformity control is to stabilize CDs across exposure fields, across wafers and across lots, for HVMs. At a current OPE matching, one usually collects tool properties from each matching tool and import them into simulation software they are using to improve its prediction accuracy. However, generally speaking, this is a time and human resource consuming process, because data acquisition from scanners usually take a lot of time of both human and machine. Furthermore, what makes it more difficult is that an OPE matching, in most cases, requires several iterations. In this paper, we will introduce our latest software named OPE-Master. By employing the software, we can expect following merits. Firstly, with the help of the software, one can be able to automatically import machine properties. This means we can expedite the iterations without sacrifice of the accuracy. Secondly, one can also be able to get better solutions, because it uses all possible adjustment knobs, some of which are ones that unable to be accessed by a third party softwares, with the help of newly developed optimization algorithm that uses a hybrid method of nonlinear optimization and rigorous simulation. Finally, intuitive interface of the software makes it possible for an engineer without much optical simulation experiences to do an OPE matching simulation. In this paper, we will also introduce one of our latest software, called CDU-Master, which will be used to control CD uniformities for a HVM. CDU-Master can analys CDs from various metrology tools, such as, CD-SEMs, OCDs or a macro inspection tools(AMI, for example). CDU-Master can decompose CD errors into focus and dose errors and then derives parameters to correct CDs. One can expect extremely high accuracy of the decomposition, because, CD-SEM as an example, it uses all possible information such as CDs and pattern 3D structure information. The correction parameters, which may include very high order coefficients to be able to deal with very high spatial frequency distribution of errors across a field or across a wafer, will be converted into a format that can be recognized by scanners and then can be exported to scanners automatically, by the software.