Plane Arrays Vertical Interconnection Technology And Reliability In Three Dimensional Assembly

With the rapid development of electronic technology, the electronic equipment is developing in a direction of miniaturization and intelligence and has reached its technical limit in two-dimensional packaging, nowadays the 3D assembly technology has attract a lot of engineers to work on it. The technology can enhance packaging density, reduce the size of equipment significantly as well as provide more I/O ports which plays an important role in achieving the miniaturization of equipment and has become the focus of packaging technique so far.The thesis studies plane arrays vertical interconnection technology in the 3Dassembly technology. The 3D assembly of three circuit boards is achieved by applying transfer board bonding with bumps on both sides and fuzz button vertical interconnection technologies. Firstly, it analyzes properties of three kinds of fuzz buttons with different materials. Then, solder balls with large size used for the 3D assembly and adapter plate by using laser soldering are prepared and developed. The 3D assembly of three circuit boards is achieved by using two kinds of vertical interconnection, which is tested by thermal shock and random vibration. At last, the response of the 3D assembly in the two tests is conducted by ANSYS and weaknesses are found out.The results show that the fuzz button has a nonlinear property in mechanical property. The mechanical model of metal wires is achieved based on three different type of contact. The resistance of fuzz button has a linear relationship with the 1/. Au/Be Cu based fuzz button possesses better elasticity and vibration resistance, Au/Mo based fuzz button has better high temperature stability, and Au/Be Cu-Mo based fuzz button owns the features of the two kinds of fuzz buttons. The solder ball made by way of remelt junction is the same with the original solder ball in internal organization. The distribution of Pb-phase is homogeneous. After being tested by thermal shock, the solder joints are most easily to fail at the corners of the adapter plate and cracks first appear near one side of the circuit board, initiate at the solder matrix near the bonding pad and propagate parallel to the bonding pad. During the process of random vibration test, fracture of solder joints with smaller size is located between the bonding pad and PCB and the 3D assembly of circuit with solder balls of larger size does not crack. ANSYS shows that the von Mises stress at the corners is larger than that of the other areas and is easiest to fail, which is in accordance with the results of the tests. It is showed by the random vibration test that A is most easily to resonant and the solder joints at the center of the adapter plate have maximum acceleration. The solder ball at the corners has the largest von Mises stress, which is the weak link of the system.