Along with the development of integrated circuits, the ignition module’s functions have improved greatly with more wires but smaller size, which cause the area occupied by pad has increased a lot. Wire bonding is a key technology to solve the product miniaturization. In order to realize the goal of smaller and lighter of ignition modules, meet customer’s demand to upgrade, Jianke bring in the deep cavity welding to minimize product’s size and enhance the stability of soldering.
Deep cavity welding belongs to wire bonding. Its principle is to vibrate elastically by ultrasonic waves while apply downward pressure. The chopper is driven by two forces, and the wire is driven to friction the metal surface of the pad area quickly and the wire deforms to closely contact with the bonding area to complete the soldering.
The two different process of gold and aluminum wires are proceed in the thousand level workshop.
To adopt which types of process depends on the specific application. Due to gold wire diameter is small, applying gold wire bonding to the chip and ceramic substrate of pressure sensors JK-SP001 can guarantee good tensile strength and extension, so it can be formed to various arcs with anti-oxidative erosion resistance and high conductivity. Meantime, it is easy to bond to the designated position via ultrasonic welding technology. High purity aluminum wire has good conductivity and anti-corrosion performance. Comparing with gold wire, it is cheaper and will not generate intermetallic compounds. Thus, the aluminum wire is used in transistor, integrated circuit assembly widely. For Jianke, ultrasonic wire bonding with heavy aluminum wire is applied to produce the plastic packaging and frame modules.
Wire bonding is the key process of production of ignition module. The correlation of human, machine, material, method and environment can impose the influence on the reliability of wire bonding to cause the failure of the circuit. The quality of wire bonding is judged by irreversible test of (bond pull test). Besides technology parameter, materials (the material, diameter, strength and tension), pad material, hook position, arc height will affect BPT result. Jianke Electronics will test and analyze the elements which may influence soldering reliability during wire bonding to prevent possible problems, so that we can enhance the reliability of wire bonding to improve the whole property.
Currently, there are new developments in the field of electric vehicles. TESLA applied wire bonding to chip’s connection solution at 2006. To TESLA, traditional soldering is time costing and prone to failure. And it is hard to detect NG between the battery and the conductor’s connection.
Wire bonding is the crucial process of production of ignition module, and for a long while, it will still be the main method for internal connecting of modules. As the packaging size is smaller, and new material and package type’s application, Jianke ‘s application of deep cavity welding will be more and more widely.