Investigation On Ultrasonic Ball Bonding And Reliability Of Integrated Circuit Packaging With Copper Wire

With the rapid development of modern science and technology and the requirement of electronic information technology, integrated circuit packaging of high density, high strength, low cost and so on the increasingly high demand. Wire bonding connected chip effect, is the key in the integrated circuit packaging process role. Conventional wire bonding process using wire bonding, but as gold prices rise and the metal itself characteristics of restricted more and more difficult to meet the growing needs of the market. The copper wire because of its low cost and its excellent electrical conductivity, thermal conductivity and stability characteristics are more and more attention and promising to replace the mainstream of wire bond. But the copper wire as bonding materials also have difficulties the process need breakthrough, Because of the high temperature wire itself is easy to oxidation and high hard ness and other characteristics, bring many unstable factors to the wire bonding process, Like easy to cause the wire does non-stick, cratering failure mode. Copper wire bonding process development time is short, parameters influencing the bonding process stability remains to be studied and optimized, the key of reliability failure mode and product copper wire bonding is the effect of copper process development. This topic will be more copper wire bonding process problems for research purposes, using the design of experiments and data analysis, the copper wire bonding process parameters and failure mode analysis, explores the reliability optimization method for copper wire bonding and copper products, the main contents are as follows:1. Design of the copper wire bonding free ball forming optimization experiment of protective gas and forming process parameters in the process of. The experimental results obtained the optimum ratio of copper wire bonding process of protective gas; after the ball size law of each parameter free ball forming process analysis under, found the main factors that affect the ball forming process is the burning time and FAB current. Copper ball size will increase with the increase of burning ball of energy. The process parameters of the copper ball forming bad analysis, found the burning time, FAB current and copper wire tail distance ignition rod the vertical distance from the impact of the most obvious.2. Analysis of the main effects of copper wire bonding process parameters, and the key parameters of ultrasonic power, the welding stress and welding time was optimized, draw a controlled ultrasonic energy range of pick-up, as access to good quality high reliability products to provide a reference direction of welding parameters optimization.3. Study on the failure mode of copper wire is easy to cause in the wire bonding process, elaborates the possible sites and causes. The copper pair process quality and yield the greatest impact solder joints do not stick(Non-stick on pad, NSOP) failure modes were analyzed in detail are caused by such failure factors and its control method.4. Analysis of the copper wire bonding failure modes in tensile test and shear test. The design of the experimental analysis of the characteristics of these failure modes are presented in the process of change over time by tensile test and shear test. Provides a reference direction and failure modes may appear in the application process for copper wire bonding.5. In order to study the reliability of copper wire bonding sealed in epoxy molding compound, the high-low temperature impact test, electrical endurance test and high temperature storage test were carried out. The results show that the bond has a good resistance of high-low temperature impact and high electrical reliability.