Wafer Bank Conversion Agreements for Agile Iso-Die Sensor Package Sourcing
Wafer bank conversion agreements convert raw iso-die into multi-form sensor packages, shifting supply risk while managing lead time, yield, and bus drift.
Wire Bonding
Connection Method
Connection quality in microelectronics depends on the formation of a solid-state weld between two metallic surfaces. A wire bonding process uses fine gold, silver, aluminum or copper wire to connect the bond pads on the chip to the leadframe. This process is the most common way to facilitate signal transfer in microelectronic devices.
It allows for a high degree of flexibility in the layout of the package.
Process Parameter
Force, time, displacement and power are the four variables that control the quality of the bond. In wire bonding, the ultrasonic transducer converts electrical energy into mechanical vibrations that break down the surface oxides. This action allows the atoms of the wire and the pad to interdiffuse and form a solid-state weld.
Calibrating the bond head and the wire tensioner is necessary to ensure the repeatability of the loop height and the bond strength. Real-time monitoring of the ultrasonic impedance provides an indication of the bond formation during the production cycle.
Quality Metric
Destructive and non-destructive tests are used to verify the mechanical integrity of the connections. Wire bonding quality is measured by the pull strength and the shear strength of the ball or wedge. A failure in the wire itself indicates a strong bond, while a failure at the interface suggests contamination or insufficient energy.
Degradation Mode
Intermetallic growth at the bond site can lead to the formation of voids over time. This phenomenon, known as the Kirkendall effect, is particularly common in wire bonding involving gold wire on aluminum pads.