Development of a Microwave Focusing Sensor and a High Resolution Imaging System for Nondestructive Evaluation of Materials

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1.Clarification of the principles of microwave focusing and reflecting by using electromagnetic wave theory A focusing sensor was developed. The microwave reflection occurring at the interface of the materials, in a small area, was analyzed. The characteristic of the microwave response relative to the size and the shape of defects, and their electromagnetic properties was clarified.2.Evaluation of delaminations with a high spatial resolution The delaminations between the lead frame and the encapsulant resin in IC packages were evaluated. The variations of the amplitude and the phase of the reflection coefficient, for the samples with and without delaminations, were observed. The parameters used for evaluation of the delamination in a high spatial resolution were obtained.3.Development of the microwave imagine system The microwave sensor was used to scan the detected object in two perpendicular directions in a plane parallel to the object. A high speed imaging system was developed, wher … More e information of the defects was recorded corresponding to the measurement position.4.Improvement of the focusing sensor For increasing the spatial resolution, the shape and the set position of the focusing sensor were optimized. The spatial resolution was further increased while a larger standoff distance between the sensor and the detected object was remained.5.Microwave applications in evaluation of the thickness of films and coating materials and the state of the interface between the coating materials and their substrates A new method for evaluation of the conductive film, which has widely been used in the manufacture of liquid crystal and solar cell etc., was investigated. Moreover, the capability of microwave to detect a small crack in the silicon film, which is used to make solar cells, was also confirmed.6.Development of the compact imagine system Based on the developed imaging system, the compact imaging system was designed fundamentally, which is expected to be used for large machines and structures in the industrial environment. A new scanning sensor was suggested for realizing the small size, low cost and popular imaging system. Less