可拉伸电子封装用局部变刚度可拉伸基板上的倒装芯片工艺

Flip Chip Process on the Local Stiffness-variant Stretchable Substrate for Stretchable Electronic Packagesstretchable packaging;stretchable substrate;PDMS;FPCB;flip chip;contact resistance;A Si chip with the Cu/Au bumps of $100-{\\mu}m$ diameter was flip-chip bonded using different anisotropic conductive adhesives (ACAs) onto the local stiffness-variant stretchable substrate consisting of polydimethylsiloxane (PDMS) and flexible printed circuit board (FPCB). The average contact resistances of the flip-chip joints processed with ACAs containing different conductive particles were evaluated and compared. The specimen, which was flip-chip bonded using the ACA with Au-coated polymer balls as conductive particles, exhibited a contact resistance of $43.2m{\\Omega}$. The contact resistance of the Si chip, which was flip-chip processed with the ACA containing SnBi solder particles, was measured as $36.2m{\\Omega}$, On the contrary, an electric open occurred for the sample bonded using the ACA with Ni particles, which was attributed to the formation of flip-chip joints without any entrapped Ni particles because of the least amount of Ni particles in the ACA.