新型可控坍塌芯片连接技术(C4)及芯下材料力学性能研究进展

NOVEL CONTROLLED COLLAPSE CHIP CONNECTION TECHNOLOGY AND STUDIES ON MECHANICAL PROPERTIES OF UNDERFILL MATERIALS

可控坍塌芯片连接 (C4)技术可以实现高速、高密度、小外形的封装 ,因此日渐得到关注和发展。然而 ,随着C4技术的普及 ,C4封装内由于芯片和基板间热膨胀系数 (CTE)的不匹配而引起的可靠性问题将日益突出 ,为此研究者在C4封装中引入芯下材料来提高C4封装的可靠性。文中侧重于制造工艺、可靠性以及最新进展对C4技术进行介绍 。

Controlled Collapse Chip Connection (C4) technology is gaining increasing popularity because it achieves high electrical interconnects speed, high density and low profile packages. While this technology gains more and more popularity, the problem of CTE mismatch between chip and substrate becomes more serious with the larger size of chips and smaller size of solder joints. Underfill encapsulant is introduced to reinforce physical, mechanical, and electrical properties of the solder joints in C4 packages. Therefore, the mechanical properties of underfill materials play an important role for the reliability of flip chip packages. In this paper, the C4 technology is introduced with emphasis on its manufacturing process, reliability, as well as some newly developments. Studies on mechanical properties of underfill materials used in C4 packaging, as well as their impacts on the reliability of C4 packages are reviewed.