A technique for the self-alignment of components is applied to the assembly of a passive micro-valve which is to be used for safety purposes in a miniature fuel cell. The technique uses the capillary forces originating in the interactions of HMDS (Hexadimethyldisilazane) and the faces of the components to achieve their passive alignment. HMDS is chosen because it is a volatile, low surface tension and inert liquid. The originality of this method is that the liquid area is defined by the edges of the components. Compared to a traditional pick-and-place technique, it leads to a leakage rate more than five times smaller.