Process and Reliability of Copper Column Flexible Flip Chip Connection (F2C2)

Abstract

reduced package footprint, and flexible column This paper addresses a new flip chip interconnect interconnections. technique -Flexible Flip Chip Connection (F2C2) technologyThe F2C2 process and structure were proposed to solve the and its initial reliability study. F2C2 utilizes copper columns CTE mismatch problem by using flexible copper columns instead of solder balls as the electrical and mechanical with the potential to eliminate the underfill process for cost interconnections between the semiconductor chip and the reduction [8, 9]. The basic F2C2 structure is presented in substrate. In this study, Accelerated Thermal Cycling (ATC) Figure 1. The F2C2 process uses a dissolvable wafer matrix tests were performed on F2C2 components as well as C4 and with an array of embedded copper wires assembled between underfill C4 components in an air-to-air thermal shock the chip and chip carrier. The wafer is composed of a heatchamber. The test results were assessed and compared. resistant, dissolvable substance to encapsulate the wires. After