Method for manufacturing a device for detecting electromagnetic radiation, including the following steps of: ∘ producing an array of thermal detectors adapted to detect electromagnetic radiation, on a readout substrate, through a first sacrificial mineral layer, the thermal detectors and the first sacrificial mineral layer being covered by a second sacrificial mineral layer; ∘ producing an encapsulation structure delimiting a cavity wherein the array of thermal detectors is located, the encapsulation structure being formed of a peripheral wall and of an encapsulation thin layer, by: • depositing the encapsulation thin layer covering the second sacrificial mineral layer; • producing vents in the encapsulation thin layer and located facing the array of thermal detectors; • partially eliminating the sacrificial mineral layers (61, 62), using wet chemical acid etching, through the vents, so as to uncover the array of thermal detectors and to obtain the peripheral wall formed of a non-etched portion of the sacrificial mineral layers (61, 62), and uncover an upper portion (31.1) of the encapsulation thin layer extending above the array of thermal detectors; ∘ characterised in that, following the chemical etching step, the peripheral wall exhibits a lateral recess resulting a vertical enlargement of the cavity, in a plane parallel to the plane of the readout substrate, between the readout substrate and the upper portion (31.1), this lateral recess defining an intermediate zone (Zr) of a surface of the readout substrate surrounding the array of thermal detectors; ∘ the method including a step of producing reinforcing pillars (31.2) of the encapsulation thin layer, arranged in the intermediate zone (Zr) around the array of thermal detectors, separate from one another and extending from the upper portion (31.1) until resting on the readout substrate. ∘ producing an array of thermal detectors adapted to detect electromagnetic radiation, on a readout substrate, through a first sacrificial mineral layer, the thermal detectors and the first sacrificial mineral layer being covered by a second sacrificial mineral layer; ∘ producing an encapsulation structure delimiting a cavity wherein the array of thermal detectors is located, the encapsulation structure being formed of a peripheral wall and of an encapsulation thin layer, by: • depositing the encapsulation thin layer covering the second sacrificial mineral layer; • producing vents in the encapsulation thin layer and located facing the array of thermal detectors; • partially eliminating the sacrificial mineral layers (61, 62), using wet chemical acid etching, through the vents, so as to uncover the array of thermal detectors and to obtain the peripheral wall formed of a non-etched portion of the sacrificial mineral layers (61, 62), and uncover an upper portion (31.1) of the encapsulation thin layer extending above the array of thermal detectors; • depositing the encapsulation thin layer covering the second sacrificial mineral layer; • producing vents in the encapsulation thin layer and located facing the array of thermal detectors; • partially eliminating the sacrificial mineral layers (61, 62), using wet chemical acid etching, through the vents, so as to uncover the array of thermal detectors and to obtain the peripheral wall formed of a non-etched portion of the sacrificial mineral layers (61, 62), and uncover an upper portion (31.1) of the encapsulation thin layer extending above the array of thermal detectors; ∘ characterised in that, following the chemical etching step, the peripheral wall exhibits a lateral recess resulting a vertical enlargement of the cavity, in a plane parallel to the plane of the readout substrate, between the readout substrate and the upper portion (31.1), this lateral recess defining an intermediate zone (Zr) of a surface of the readout substrate surrounding the array of thermal detectors; ∘ the method including a step of producing reinforcing pillars (31.2) of the encapsulation thin layer, arranged in the intermediate zone (Zr) around the array of thermal detectors, separate from one another and extending from the upper portion (31.1) until resting on the readout substrate.