To provide a stabilization treatment method capable of realizing a stable operation of AVC by further heating (annealing) an organic substance at a high temperature after reflow, in consideration that a drift in the AVC using an organic substance hinge is caused by mechanical, chemical, or electrical instability after reflow, and improve an MEMS element containing the organic substance as at least one of the constituent substances.

An organic substance is treated by hydrogen fluoride after cross-link by heating, and is stabilized by annealing it at a prescribed temperature or more, for a prescribed time period or more (particularly 200C or more and 250C or less for 3 hours or more). The organic substance is mainly composed of tetra-methyl-siloxane-divinyl-benzocyclobutene.