Substrate bonding using a selenidation reaction

Abstract

A selenidation reaction for bonding one or more active substrates to a base substrate is disclosed. A bonded-substrate is fabricated by forming a first multi-stacked layer of selenium and indium on a bonding surface of an active substrate and forming a second multi-stacked layer of selenium and indium on a mounting surface of a base substrate. The first and second multi-stacked layers are placed into contact with each other with substantially no pressure. Then the active substrate and the base substrate are bonded to each other by annealing them in an inert ambient to form an indium-selenium compound bond layer that adhesively bonds the substrates to each other. The annealing can occur at a lower temperature than prior wafer-bonding processes and the first and second multi-stacked layers can be deposited over a wide range of relatively low temperatures including room temperature. Additionally, tellurium can be added to the selenium of either one or both of the first and second multi-stacked layers to reduce the annealing temperature and to form an indium-selenium-tellurium compound bond layer that adhesively bonds the substrates to each other. Elemental compounds or amorphous compounds can be used for the materials of the first and second multi-stacked layers to form a polycrystalline or amorphous compound bond layer respectively. One advantage of the compound bond layer is that it can be dissolved using a selective wet etching material so that the active substrate and the base substrate can be non-destructively detached from each other.