Impact of warpage on signal delivery with large size FC-PBGA package

Abstract

The impact of non-zero warpage on signal delivery characteristics is presented by analyzing transmission line on curved plane defined in cylindrical coordinate system. Authors will present a compact finite-difference frequency-domain method for quasi-TEM mode (C-FDFD-QT) with cylindrical coordinate system, which is a promising method to determine the characteristic impedance with efficiently reduced size of computational matrix by using quasi-TEM approximation. In summary, the non-zero warpage of large-size substrate constructing large size FC-BGA results in the increase of characteristic impedance, which has been quantitatively studied by using C-FDTD-QT. The characteristic impedance of stripline on curved plane is larger than that of stripline on the plane whose warpage is zero.