Attaching an smd to an insulating layer with a solder joint in a cavity formed in an insulating layer

A process for attaching an electronic component to a printed circuit, said printed circuit comprising a connecting surface having at least one conductive layer and defining an axis Z, said axis Z being normal to the connecting surface, the attachment process S comprising the following steps:

• applying an insulating layer comprising an electrically insulating material to the connecting surface of the printed circuit, the insulating layer having a minimum thickness determined along the axis Z,
• forming a cavity in the insulating layer above the conductive layer so that at least part of the conductive layer is exposed, the cavity having a minimum depth determined along the axis Z,
• filling the cavity with a metal alloy accompanied by a soldering flux
• positioning the electronic component over the cavity,
• applying a heat treatment to the printed circuit on which the component is placed in order to transform the metal alloy together with the soldering flux into a solder joint so as to attach the component to the printed circuit,
• the minimum thickness of the insulating layer is such that the depth of the cavity is at least equal to 100 μm, and
• wherein the electrically insulating material of the insulating layer has a first coefficient of thermal expansion along the axis Z, the metal alloy has a second coefficient of thermal expansion along the axis Z, and wherein the first coefficient of thermal expansion is greater than the second coefficient of thermal expansion.