Localized　recrystallization　occurs　in　Pb-free　solder　joints　under　thermomechanical　fatigue　stress　(thermal　fatigue).　Scanning　electronic　microscopy　and　electron　backscattered　diffraction　were　used　to　obtain　the　microstructures　and　grain　orientations,　respectively,　of　Sn3.5Ag　solder　bumps　after　shear　testing.　At　room　temperature,　recovery　and　continuous　recrystallization　tend　to　occur　at　the　near-pad　interface　and　near-shear　edge　regions　of　the　solder　bumps　under　shear　stress.　A　(sub)grain　rotation　mechanism　dominates　the　recrystallized　(sub)grains,　distinguishing　them　from　the　initial　orientations.　Additionally,　the　rotation　axis　and　angle　were　investigated　to　further　elucidate　the　recrystallized　(sub)grain　rotation　behavior　of　Pb-free　solder　bumps.　The　results　show　the　formation　of　a　single　rotation　axis　between　a　(sub)grain　and　its　neighboring　(sub)grain　during　recrystallization,　indicating　a　relationship　between　continuous　recrystallization　and　the　Sn　slip　systems　in　Pb-free　solder　alloys.