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，许多键合技术都应用于小面积或薄层，键合不良可能导致电气故障。因此，需要对微键合区进行在线或在线检测，以保证电子器件的质量。然而，很少有技术适用于微键合区域。在这项研究中，提出了两种方法的非破坏性评估的小或薄的键合区域的微电路。第一种方法是用延迟线对引线键合区域进行超声检测。另一种是用聚焦探头对芯片键合进行超声检测。主要研究结果如下：1.引线键合延迟线超声检测提出了一种延迟线超声检测方法。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， ...更多信息 在push测试中。由于断裂载荷对应于引线键合状态，因此该方法能够对引线键合进行非破坏性评估。虽然反射波的大小取决于测量压力、探针与毛细管的接触以及耦合剂的大小，但测量压力与键合过程的条件相同，表明该方法适用于引线键合过程的在线测量。2.聚焦探头的芯片键合超声检测一种新开发的聚焦探头超声检测方法应用于芯片键合区域，其中膏以0.15 mm厚的基板和0.29 mm厚的微电路之间的薄层提供。在光程小于超声束焦距的测量条件下，检测到从基片与浆料界面反射的界面回波，其滞后于表面回波的时间可观测到。扫描中的界面回波显示了与缺膏和脱粘相对应的振幅变化。在挥发性液体中的测量防止了微电路对水的腐蚀和吸收，并且在水中显示出相同的结果。挥发性液体中的超声波检测可用于微小器件的在线检测。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