Method for bonding and interconnecting integrated circuit devices

A method for bonding and interconnecting a first IC device arranged on a first substrate to a second IC device arranged on a second substrate, wherein each IC device comprises a dielectric bonding layer at its outer surface, and wherein each IC device further comprises one or more metal contact structures, the method comprising the consecutive steps of:

• positioning the first substrate with respect to the second substrate, with the bonding layers of the first and second IC device facing each other, by aligning a first metal contact structure in the first IC device to a second metal contact structure in the second IC device;
• direct bonding of the substrates, thereby forming a substrate assembly;
• optionally thinning the first substrate;
• producing by a lithography step and an etching procedure, a first opening in the first substrate, until reaching the first metal contact structure, wherein the first metal contact structure partially covers a cross-section of the first opening;
• with the first metal contact structure acting as a mask, etching one or more second openings in the second substrate, stopping on the second metal contact structure, the first and second opening thereby forming an aggregate opening;
• producing an isolation layer on the sidewalls and the bottom of at least the first opening;
• removing the isolation layer from at least the bottom of the first opening, while maintaining the isolation layer on at least the sidewalls of the first opening, without applying a lithography step;
• and
• producing a metal contact plug in the aggregate opening, the metal plug interconnecting the first and second contact structures,
• wherein the step of removing the isolation layer is performed by a plasma treatment comprising the steps of
• introducing the assembly in a plasma atmosphere comprising one or more polymer-forming components and one or more etching components,
• treating the assembly by inducing a plasma such that a protective polymer layer is formed on at least portions of the isolation layer present on the upper surface of the assembly and on at least portions of the isolation layer present on upper portions of the sidewalls of the first opening, thereby protecting the portions of the isolation layer where the protective polymer layer is being formed, from the plasma, wherein portions of the isolating layer being exposed to the plasma are etched, and wherein the plasma is induced by radio frequency power, and
• wherein the radio frequency power comprises a low frequency component providing acceleration of ions in the plasma and a high frequency component sustaining the plasma and controlling a density of the plasma.

A method for bonding and interconnecting a first IC device arranged on a first substrate to a second IC device arranged on a second substrate, wherein each IC device comprises a dielectric bonding layer at its outer surface, and wherein each IC device further comprises one or more metal contact structures, the method comprising the consecutive steps of:

• positioning the first substrate with respect to the second substrate, with the bonding layers of the first and second IC device facing each other, by aligning a first metal contact structure in the first IC device to a second metal contact structure in the second IC device;
• direct bonding of the substrates, thereby forming a substrate assembly;
• optionally thinning the first substrate;
• producing by a lithography step and an etching procedure, a first opening in the first substrate, until reaching the first metal contact structure, wherein the first metal contact structure partially covers a cross-section of the first opening;
• with the first metal contact structure acting as a mask, etching one or more second openings in the second substrate, stopping on the second metal contact structure, the first and second opening thereby forming an aggregate opening;
• producing an isolation layer on the sidewalls and the bottom of at least the first opening;
• removing the isolation layer from at least the bottom of the first opening, while maintaining the isolation layer on at least the sidewalls of the first opening, without applying a lithography step;
• and
• producing a metal contact plug in the aggregate opening, the metal plug interconnecting the first and second contact structures, wherein at least the first opening is formed by an essentially anisotropic etching procedure for producing an opening having an essentially constant cross-section, followed by an isotropic etching procedure, configured to create or enhance one or more overhang areas in the opening.