We have developed 3D-Measuring-Modelling System, which can be applied to any object from small to large size, using a note PC and digital cameras. This time, especially in view of its application to the area of industrial measurement, we have endeavored to attain higher accuracy in 3D measurement (from former 0.26mm to present below 0.1mm) as well as the further simplification of the measuring operation. For this purpose we have developed a scale bar and other peripheral devices and we assessed the resulted accuracy. Therefore, today we should like to report on the new system thus developed and its accuracy assessment, as well as its various application examples in automobile measurement.
We report about three-dimensional measurement by CD-SEM. Last year, we reported that the new T-MOL (Tilting and Moving Objective Lens) electron optical system enabled the capture of tilt images without deterioration of the resolution and confirmed that the T-MOL system provides 4 nm resolution at tilting angle 5 degrees. In this year we developed and evaluated the new objective lens and the new octapole deflector for increase of tilting angle and improvement in resolution, and we confirmed that the new electron optical system provides 3.6 nm resolution at tilting angle 8 degrees. Moreover, we report the optimization of the stereo matching technique based on the tilting picture using the actual semiconductor device for measurement 3D analysis.
There is an increasing necessity for 3D measurement of formed patterns in the semiconductor manufacturing process, and the development of the 3D measurement technology is required even in CD-SEM. In order to obtain 3D images, it is necessary to acquire at least two tilted images from different directions. However, the procedure of tilting the specimen stage is disadvantageous from the throughput point of view. Therefore, we devised the T-MOL system, which enables the acquisition of tilt images without the deterioration of the resolution by tilting the primary electron beam. Moreover, the algorithm of the parallel projection for the 3D reconstruction was developed. Tests proved that new T-MOL electron optical system provides 4nm resolution tilting angle at 5 degrees and that 3D analysis based on T-MOL images is effective.