Method for Forming Isolation Trenches in Micro-Bump Interconnect Structures and Devices Obtained Thereof

A method for producing a substrate suitable for use in a stack of interconnected substrates, comprising the steps of:

• providing a substrate, the substrate comprising:
• a base layer, having a front side and a back side parallel to a plane of the base layer,
• one or more vias filled with an electrically conductive material, said vias running through a complete thickness of the base layer, said filled vias forming an electrical connection from the back side to the front side of the base layer,
• etching one or more ring-shaped trenches in the back side of said base layer, each of said ring-shaped trenches surrounding one or more of said filled vias, and
• on the back side of the base layer:
• producing a landing pad and a micro-bump in electrical connection with said filled via, wherein each of said ring-shape trenches surrounds one or more of said micro-bumps.

A method for producing a stack of interconnected substrates, the method comprising the steps of:

• stacking two or more substrates, wherein one or more of said substrates comprises:
• a base layer, having a front side surface and a back side surface parallel to a plane of the base layer;
• one or more interconnect structures;
• and
• one or more isolation ring trenches, each of said isolation ring trenches surrounding one or more of said interconnect structures;
• placing an underfill material between neighbouring substrates of said substrates;
• and
• curing said underfill material so as to form a bond between said neighbouring substrates.