Estimation Of Thermal Fatigue Life Of TSV Solder Joints And Uncertainty Study

With the improving of the demand for product function, the bottleneck problems that the traditional two-dimensional electronic packaging technology faces is more and more prominent, 3D integration technology has gradually become the mainstream. TSV(Through Silicon Via) technology makes vertical through via between chips vs. chips and wafers vs. wafers, and fills conductor in the through via, realize the interconnection between the chips. The advantages of the chip interconnect way are small package volume, strong performance, fast signal transmission speed, but the overall heat dissipation capacity reduces. One of the main challenges TSV technology faces is still concentrated on the failure problems associated with heat. In addition, the deterministic parameters and mathematical models of numerical simulation method are widely used in integrated circuit packaging design work. But, in fact, there are different levels of uncertainty in any actual structure, making an uncertain problem as a deterministic problem to calculate, the result will be too conservative, interval analysis method provides a path for this kind of problem.This paper focus on heat failure problem of the solder joints in 3D TSV technology packaging components and makes a series of research work. The main contents are as follows:1、The reasonable simplified two-dimensional model with deterministic parameters based on 3D TSV technology interconnection structure model is set up by using finite element software ANSYS. According to viscoplastic constitutive Anand equation which is used to describe the mechanical behavior of SnPb solder joints with JEDEC standard temperature load, analyze the temperature field and coupled thermal-mechanical under thermal cyclic loading of TSV interconnection structure model. Depend on the stress/strain peak distribution and the time history curve, the danger position of solder joint is found directly. Moreover, in order to estimate reliability of the product, use the Engelmaier empirical equation to calculate the thermal fatigue life cycle of risky solder joints.2、In part of this paper a series of research has been carried out on thermal fatigue life of solder joints by changing a single parameter, including the chip size, chip layer, substrate thickness and through via depth, diameter, spacing data. Each column joints are recorded such as temperature, stress and strain. In addition, fitting curves are made to summarize the changing trend, compare and analyze the parameters to find out changing degree of solder joints fatigue life, and sum up variable of fatigue life in order to provide theoretical reference for design and optimization work.3、Since there are many uncertain factors of the TSV structure model in the process of calculation, considering thermal physical property parameters, structure size and other uncertain parameters as interval variables, combined with finite element method and interval analysis method, transient thermal interval uncertainty analysis of TSV structure is accomplished.According to heat coupling calculation of TSV model based on the certain parameters and interval analysis with uncertain parameters, this paper gets the size parameters of the model structure and material physical parameters how to influence the solder joints fatigue life and provides a valuable reference for the further study of electronic packaging thermal dissipation.