Process for fabricating an integrated circuit comprising hollow trench isolations in a substrate and active components in and on active zones of the substrate, these zones being arranged between said trench isolations, said process comprising: - forming hollow trench isolations within a substrate; and - producing active components in and on the active zones of the substrate, these zones being arranged between said trench isolations, wherein: - the operation of forming the trench isolations comprises: - an initial phase carried out before the operation of producing the active components and including: * an operation of forming trench isolations in the substrate; and * an operation of filling the trench isolations with a filler material; and - a final phase carried out before the operation of producing the active components and including: * an operation of encapsulating the active components; * an operation of making an access well through the encapsulation material to each filled trench isolation; * an operation of removing the filler material from the trench isolations through each well; and * an operation of filling in the opening in each trench isolation through the corresponding access well, hollow trench isolations thus being formed. - forming hollow trench isolations within a substrate; and - producing active components in and on the active zones of the substrate, these zones being arranged between said trench isolations, wherein: - the operation of forming the trench isolations comprises: - an initial phase carried out before the operation of producing the active components and including: * an operation of forming trench isolations in the substrate; and * an operation of filling the trench isolations with a filler material; and - a final phase carried out before the operation of producing the active components and including: * an operation of encapsulating the active components; * an operation of making an access well through the encapsulation material to each filled trench isolation; * an operation of removing the filler material from the trench isolations through each well; and * an operation of filling in the opening in each trench isolation through the corresponding access well, hollow trench isolations thus being formed. - the operation of forming the trench isolations comprises: - an initial phase carried out before the operation of producing the active components and including: * an operation of forming trench isolations in the substrate; and * an operation of filling the trench isolations with a filler material; and - a final phase carried out before the operation of producing the active components and including: * an operation of encapsulating the active components; * an operation of making an access well through the encapsulation material to each filled trench isolation; * an operation of removing the filler material from the trench isolations through each well; and * an operation of filling in the opening in each trench isolation through the corresponding access well, hollow trench isolations thus being formed. - an initial phase carried out before the operation of producing the active components and including: * an operation of forming trench isolations in the substrate; and * an operation of filling the trench isolations with a filler material; and * an operation of forming trench isolations in the substrate; and * an operation of filling the trench isolations with a filler material; and - a final phase carried out before the operation of producing the active components and including: * an operation of encapsulating the active components; * an operation of making an access well through the encapsulation material to each filled trench isolation; * an operation of removing the filler material from the trench isolations through each well; and * an operation of filling in the opening in each trench isolation through the corresponding access well, hollow trench isolations thus being formed. * an operation of encapsulating the active components; * an operation of making an access well through the encapsulation material to each filled trench isolation; * an operation of removing the filler material from the trench isolations through each well; and * an operation of filling in the opening in each trench isolation through the corresponding access well, hollow trench isolations thus being formed.