The present invention relates to a process for producing a fuel cell, comprising a step of forming a plurality of holes (10) in at least two substrates (9); each hole is in the seat of an individual fuel cell, the said holes having a particular geometry, such as a shape of a truncated cone or a truncated pyramid shape.The various individual cells are then electrically connected by networks of electrical connections (11, 12) and are supplied via a reactant distribution network, the assembly formed by a substrate (9), the cells and the networks constituting a base module (9'). Finally, at least two base modules (9') are assembled, the individual cells of each base module being positioned facing the individual cells of the adjacent base module(s).