Design and electrical performance analysis on coreless flip chip BGA substrate

The advantage and reason, including electrical performance, design flexibility and potential cost saving, to adopt a coreless organic substrate in a FCBGA package is described. Especially, the cross talk and insertion loss comparison analysis between normal thick core and coreless FCBGA is presented, and there is about 10~20 dB cross talk improvement for the coreless substrate design over the thick core substrate. However, the coreless doesn't has better insertion loss as expectation due to poor impedance control near solderball locations. In this paper, also propose the design optimization when coreless substrate is implemented.