Online methods to measure breaking force of bonding wire using a CMOS stress sensor and a proximity sensor (original) (raw)
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IEEE Transactions on Components, Packaging and Manufacturing Technology, 2013
ABSTRACT A ball bonding process in wire bonding generally involves impact followed by ultrasonic (US) bonding prior to wedge bonding. During the ball bonding process, the impact force flattening the free-air ball introduces significant localized out-of-plane compressive stress on the pad and the low-k structure beneath. The subsequent process of US bonding induces in-plane and shear stresses to the structure. High induced stress during bonding is not desirable, as it may lead to pad damage or cratering of the silicon structure. In this paper, we report on studies conducted on using four piezoresistive sensors embedded underneath the center of the bond pad for the evaluation of in-plane and out-of-plane stresses, which covers both the impact and US stages during the ball bonding process. Different levels of impact force, bond force, bonding duration, and US power are investigated using gold wire bonding for feasibility and sensitivity studies of the stress sensors. Fast Fourier transform (FFT) and inverse FFT are used for noise filtering and to isolate the US signal yielding a continuous output signal from the in situ measurement of contact and US stages during the ball bonding process. It is found that the stress sensors are sensible to capture different impact force, bond force, bonding duration, and US power.
In situ ultrasonic force signals during low-temperature thermosonic copper wire bonding
2008
Ultrasonic in situ force signals from integrated piezo-resistive microsensors were used previously to describe the interfacial stick-slip motion as the most important mechanism in thermosonic Au wire ball bonding to Al pads. The same experimental method is applied here with a hard and a soft Cu wire type. The signals are compared with those obtained from ball bonds with standard Au wire.
New Generation Semi-Automatic Thermosonic Wire Bonder
Journal of Electronic Research and Application
The physical and technological aspects of wire ball-wedge bonding in the assembly of integrated circuits are considered. The video camera and the pattern recognition system (PRS) of new bonder helps to provide accurate positioning of the bonding tool on the chip pads of integrated circuits. The formation of the loop wire cycle is ensured by the synchronous movement of the bonding head along the Z axis and the working table along the XY axes based on the servo drive. A feature of the bonder is that it can bond all the wire loops of the electronic device according to the pre-recorded program without needing to align the bonding points.