As the design rule becomes continuously smaller, the Hard OPC is being applied to pattern design in semiconductor
production. Controllability of hard OPCed pattern’s quality directly affects to the performance of the device and yields of
production. Critical Dimension Scanning Electron Microscopy (CD-SEM) is used to accurately confirm the Critical
Dimension (CD) quality of the photomask. CD-SEM makes the pattern’s shape image by using secondary electrons
information directly from the Mask surface and can measure CD values. Classically the purpose of CD-SEM
measurement was to get one dimensional CD values. However it is difficult to guarantee complex hard OPCed pattern’s
quality by using only one dimensional CD values because complexity of pattern design has been increased.
To confirm and control the quality of hard OPCed pattern, the quality of pattern fidelity must be measured
quantitatively. In order to overcome this difficulty we developed a new method to quantitatively evaluate the quality of
pattern fidelity using EPE (Edge Placement Error) distance from the overlay between Target Design GDS and SEM GDS
contour which is extracted from CD-SEM image. This paper represents how to define and analyze quantitatively the
quality of complex hard OPCed pattern.
As design rules of lithography shrink: accuracy and precision of Critical Dimension (CD) and controllability of hard OPCed patterns are required in semiconductor production. Critical Dimension Scanning Electron Microscopes (CD SEM) are essential tools to confirm the quality of a mask such as CD control; CD uniformity and CD mean to target (MTT). Basically, Repeatability and Reproducibility (R and R) performance depends on the length of Region of Interest (ROI). Therefore, the measured CD can easily fluctuate in cases of extremely narrow regions of OPCed patterns. With that premise, it is very difficult to define MTT and uniformity of complex OPCed masks using the conventional SEM measurement approach. To overcome these difficulties, we evaluated Design Based Metrology (DBM) using Large Field Of View (LFOV) of CD-SEM. DBM can standardize measurement points and positions within LFOV based on the inflection/jog of OPCed patterns. Thus, DBM has realized several thousand multi ROI measurements with average CD. This new measurement technique can remove local CD errors and improved statistical methodology of the entire mask to enhance the representativeness of global CD uniformity. With this study we confirmed this new technique as a more reliable methodology in complex OPCed patterns compared to conventional technology. This paper summarizes the experiments of DBM with LFOV using various types of the patterns and compares them with current CD SEM methods.
As improving device integration for the next generation, high performance and cost down are also required
accordingly in semiconductor business. Recently, significant efforts have been given on putting EUV
technology into fabrication in order to improve device integration. At the same time, 450mm wafer
manufacturing environment has been considered seriously in many ways in order to boost up the productivity.
Accordingly, 9-inch mask has been discussed in mask fabrication business recently to support 450mm wafer
manufacturing environment successfully. Although introducing 9-inch mask can be crucial for mask industry,
multi-beam technology is also expected as another influential turning point to overcome currently the most
critical issue in mask industry, electron beam writing time. No matter whether 9-inch mask or multi-beam
technology will be employed or not, mask quality and productivity will be the key factors to survive from the
device competition. In this paper, the level of facility automation in mask industry is diagnosed and analyzed
and the automation guideline is suggested for the next generation.
As the design rule of lithography becomes smaller, accuracy and precision in Critical Dimension (CD) and
controllability of pattern-shape are required in semiconductor production. Critical Dimension Scanning Electron
Microscope (CD SEM) is an essential tool to confirm the quality of the mask such as CD control, CD uniformity and CD
mean to target (MTT). Unfortunately, in the case of extremely rounded region of arbitrary enclosed patterns, CD
fluctuation depending on Region of Interest (ROI) is very serious problem in Mask CD control, so that it decreases the
yield. In order to overcome this situation, we have been developing 2-dimensonal (2D) method with system makers and
comparing CD performance between mask and wafer using enclosed arbitrary patterns. In this paper, we summarized the
results of our evaluation that compare error budget between 1-dimensonal (1D) and 2D data using CD SEM and other
optical metrology systems.
High aspect ration resist patterns with dimensions below 100 nm often bend, break or tear. These phenomena are generically called “resist pattern collapse”. Pattern collapse is a very serious problem in fine patterning of less than 100 nm critical dimension (CD), so that it decreases the yield. In order to mechanically analyze this phenomenon and create its simulator, two models have been made and compared. In this paper, various approaches with various analyses are made to understand pattern collapse. Also, the critical aspect ratio for 100 nm node, that determines whether pattern collapse happens or not, can be calculated with these approaches. Finally tear type caused by insufficiency of adhesion strength between the substrate and the resist is analyzed with a point of view of the surface free energy.