Development of a Millimeter-Wave Imaging Compact System & Contaceless and Quantitative Evaluation of Delamination and Crack with High Spatial Resolution

1. 微波无损检测通常采用网络分析仪作为检测设备。但网络分析仪体积较大，价格较高。因此，很难在工业环境中使用它。因此，开发了一种毫米波紧凑型设备来克服这些问题。该装置可以很好地完成幅值和相位的测量。毫米波反射聚焦传感器的研制研制了一种利用两个椭球反射面进行材料无损检测的毫米波聚焦传感器。采用聚焦传感器，有效地扩大了传感器与样品之间的升空距离，同时获得了更高的空间分辨率。电子器件和高空间分辨率薄膜的缺陷检测和电特性评价采用毫米波成像技术对IC封装中芯片衬垫和封装树脂之间可能发生的分层现象进行了检测。成功地检测到全部和部分脱层。此外，还开发了一种非接触测量导电薄膜（如氧化铟锡薄膜）电导率的方法。利用毫米波紧凑设备成功地进行了测量。金属表面闭合小裂纹的定量评价采用双频技术对二维小裂纹深度进行评价，其中裂纹闭合情况未知。另一方面，提出了一种计算裂纹闭合应力的方法。评价了闭合应力对双频技术的影响。此外，为了评价三维裂纹，在修正双频方程的基础上，引入了干涉波形分量，成功地评价了三维小裂纹的形状和尺寸。

1. Development of a compact imaging systemUsually, network analyzer is used as the equipment for microwave nondestructive testing. However, network analyzer has lager size and its price is high. Hence it becomes difficult to use it in the industrial environment. Therefore, a millimeter-wave compact equipment was developed to overcome these problems. Both the amplitude and the phase measurement can well be carried out by the compact equipment.2. Development of a millimeter-wave reflection focusing sensorA millimeter-wave focusing sensor utilizing two ellipsoidal reflectors woo developed for nondestructive evaluation of materials. By using the focusing sensor, liftoff distance between the sensor and sample woo effectively enlarged, while a higher spatial resolution was also obtained.3. Detection of defects and evaluation of electrical characteristics in electronic devices and thin films with high spatial resolutionThe delamination, which may occur between the chip pad and the encapsulate resin in IC packages, was inspected by millimeter-wave imaging technique. The full and part delamimations were successfully detected. Also a method for contactless measurement of the conductivity of thin conducting films, such us Indium Tin Oxide film, was developed. The measurement was successfully carried out by using the millimeter-wave compact equipment.4. Quantitative evaluation of closed small cracks on the metal surfaceA dual frequency technique was developed to evaluate the depth of small 2-D cracks of which situation regarding crack closure is unknown. On the other hand, a method to evaluate closure stress of cracks was developed. The effect of closure stress on the dual frequency technique was evaluated. In addition, to evaluate 3-D cracks, from the modified dual frequency equation, a new component named interference waveform was introduced, by which the shape and size of small 3-D cracks were successfully evaluated.