Method for manufacturing a detection device comprising an encapsulation structure comprising a thin opaque layer resting on a mineral peripheral wall

A method for manufacturing a device for detecting electromagnetic radiation, comprising the following steps of:

• producing a detection array formed of thermal detectors intended to detect the electromagnetic radiation, and of at least one compensation array formed of thermal detectors intended not to detect the electromagnetic radiation, on and through a first sacrificial layer resting on a reading substrate,
• the thermal detectors of the compensation array being configurated to detect the electromagnetic radiation and structurally identical to the thermal detectors of the detection array;
• producing a second sacrificial layer covering the thermal detectors and the first sacrificial layer;
• producing a secondary encapsulation structure delimiting a secondary cavity wherein the compensation array is located, and comprising a peripheral wall as well as an opaque upper wall resting on the peripheral wall and formed of at least one thin opaque layer;
• wherein:
• the first and second sacrificial layers are made of a mineral material;
• the step of producing the secondary encapsulation structure comprises the following steps of:
• producing the thin opaque layer so that it extends in a continuously planar manner only along an upper surface of the second mineral sacrificial layer;
• producing, in the thin opaque layer, vents disposed facing the compensation array;
• partially removing the first and second mineral sacrificial layers through the vents, by chemical etching, so as to release the detection array and the compensation array, and to obtain the peripheral wall then formed of a non-etched portion of the mineral sacrificial layers and surrounding the compensation array, the thin opaque layer then being suspended above the compensation array and resting on the peripheral wall.