An original strategy is described to address a critical issue for flexible and stretchable electronics. For the first time, buckling of prestrain-free stiff film (spontaneous buckling) is achieved on composite substrate benefiting from fibrous nature of daily life substrates such as paper, textiles or bandage. This new strategy allows the processing of microstructures which are directly embedded in a fibrous substrate during fabrication process. Multiaxially compressive strain due to fibrous material shrinkage is strong enough to induce multiaxially stiff film buckling. Moreover, additional fibrous material prestretching leads to enhance the buckling effect allowing buckled ribbons use as interconnections. As a result, 80% maximum elongation is obtained before interconnections mechanical and electrical failure.