A process for closure of at least one cavity intended to encapsulate or be part of a microelectronic device, comprising the following steps: a) Producing a cavity in a first substrate comprising a first layer traversed by an opening forming an access to the cavity; b) Producing a portion of bond material around the opening, on a surface of the first layer located on the side opposite the cavity; c) Producing, on a second substrate, a portion of fusible material, with a deposition of the fusible material on the second substrate and the use of a mask; d) Placing the portion of fusible material in contact with the portion of bond material; e) Forming a plug for the opening, which adheres to the portion of bond material, by melting and then solidification of the fusible material; f) Separating the plug and the second substrate.