Development of In-Process Ultrasonic Measurement For Quality Assurance of Microjoints in Electronic Devices

在电子器件的组装过程中，许多粘接技术都应用于小面积或薄层，粘接不良可能导致电气故障。因此，为了保证电子器件的质量，需要对微键合区进行在线或制程测试。然而，目前适用于微保税区的技术很少。在本研究中，提出了两种方法来无损评估微电路中小或薄的键合区域。第一种方法是用延迟线对焊丝保税区进行超声波检测。另一种是用聚焦探头对模具键合进行超声检测。得到的结果如下：1。提出了一种延迟线超声检测方法，延迟线采用粘接工具或毛细管与探头连接。在这种方法中，通过毛细管的反射波的振幅变化与断裂载荷成正比。由于断裂载荷与金属丝粘接状态相对应，因此该方法可以对金属丝粘接进行无损评价。虽然反射波取决于测量压力、毛细管与探头和耦合器的接触，但测量压力与键合过程相同的条件表明，该方法适用于导线键合过程中的测量。采用聚焦探头对模具粘接区域进行超声检测，在0.15 mm厚的基板和0.29 mm厚的微电路之间的薄层中提供浆料。在水程比超声波束焦距短的测量条件下，检测到基材与膏体交界面反射的界面回波，表面回波后存在可观测的时间延迟。扫描过程中界面回波显示出相应的幅值变化，表明膏体缺失和脱粘。在挥发性液体中的测量可以防止微电路受到水的腐蚀和吸收，并且在水中显示相同的结果。在挥发性液体中进行超声波检测可用于微器件的在线测量。少

In the assembly process of electronic devices, many bonding techniques are applied to the small area or thin layr, in which poor bonding may result in electrical failures. Therefore, in-line or in-process testing of micro bonded area are demanded for the quality assurance of electronic devices. However, there are few techniques applicable to the micro bonded area. In this study, two methods are proposed for the non-destructive evaluation of small or thin bonded area in the microcircuit. First method is the ultrasonic testing of wire bonded area with a delay line. Another one is the ultrasonic testing of die bonding with a focused probe. The results obtained are as follows.1.Ultrasonic testing of wire bonding with a delay lineAn ultrasonic testing with delay line is proposed, in which a bonding tool or capillary is used for the delay line and is connected to the probe. In this method, the reflected wave through the capillary indicates proportional amplitude change to the fracture load i … More n the push test. Since the fracture load corresponds to the wire bonding state, this method enables the non-destructive evaluation of wire bonding. Although the reflected wave depends upon the measuring pressure, contact of capillary with probe and couplant, the same condition of measuring pressure to bonding process suggests that this method is applicable to the in-process measurement of wire bonding.2.Ultrasonic testing of die bonding with a focused probeA newly developed ultrasonic testing with a focused probe is applied to the die bonded area, where the paste is supplied in the thin layr between 0.15 mm thick substrate and 0.29 mm thick microcircuit. Under the measuring condition of shorter water path than the focal length of ultrasonic beam, the interface echo reflected from the interface between the substrate and paste is detected with an observable time delay behind surface echo. The interface echo in the scanning indicates the corresponding amplitude change to the lack of paste as well as the debonding. The measurement in the volatile liquid prevents the microcircuit from the corrosion and absorption of water, and shows the same results in the water. The ultrasonic testing in the volatile liquid is available to the in-line measurement of micro devices. Less