Multiple chip module (MCM) structures are described. In an embodiment, a module includes a first and second components on the top side of a module substrate, a stiffener structure mounted on the top side of the module substrate, and a lid mounted on the stiffener structure and covering the first component and the second component. The stiffener is joined to the lid within a trench formed in a roof of the lid.

A hermetic package comprising a substrate (110) having a surface with a MEMS structure (101) of a first height (101a), the substrate hermetically sealed to a cap (120) forming a cavity over the MEMS structure; the cap attached to the substrate surface by a vertical stack (130) of metal layers adhering to the substrate surface and to the cap, the stack having a continuous outline surrounding the MEMS structure while spaced from the MEMS structure by a distance (140); the stack having a bottom first metal seed film (131a) adhering to the substrate and a bottom second metal seed film (131b) adhering to the bottom first seed film, both seed films of a first width (131c) and a common sidewall (138); further a top first metal seed film (132a) adhering to the cap and a top second metal seed film (132b) adhering to the top first seed film, both seed films with a second width (132c) smaller than the first width and a common sidewall (139); the bottom and top metal seed films tied to a metal layer (135) including gold-indium intermetallic compounds, layer (135) having a second height (133a) greater than the first height and encasing the seed films and common sidewalls.

A hermetic package comprising a substrate (110) having a surface with a MEMS structure (101) of a first height (101a), the substrate hermetically sealed to a cap (120) forming a cavity over the MEMS structure; the cap attached to the substrate surface by a vertical stack (130) of metal layers adhering to the substrate surface and to the cap, the stack having a continuous outline surrounding the MEMS structure while spaced from the MEMS structure by a distance (140); the stack having a bottom first metal seed film (131a) adhering to the substrate and a bottom second metal seed film (131b) adhering to the bottom first seed film, both seed films of a first width (131c) and a common sidewall (138); further a top first metal seed film (132a) adhering to the cap and a top second metal seed film (132b) adhering to the top first seed film, both seed films with a second width (132c) smaller than the first width and a common sidewall (139); the bottom and top metal seed films tied to a metal layer (135) including gold-indium intermetallic compounds, layer (135) having a second height (133a) greater than the first height and encasing the seed films and common sidewalls.