Authors: Andreas Ostmann Company: Technical University of Berlin Date Published: 9/10/1996
Surface Mount International
Abstract: Flip chip (FC) technology arrived an increased level of acceptance for many different applications. The first driving force for the introduction of this technology was the need to achieve increased speed and performance along with higher J/O count. A breakthrough, however, will be the use of flip chip due to cost reduction. For this aim it is essential to use low cost bumping techniques in combination with an assembly method compatible to existing SMT processes. The FC techniques presented in this paper are all based on an electroless Ni/Au bumping process which has been developed by TUB/IZM. On the Ni bumps solder is applied either by stencil printing or by placement of pre-formed solder balls. For the FC interconnection solder can be applied on the chips or on the substrate material. FC assembly has been performed on organic substrates (FR4) by a SMT compatible reflow.