Area selective deposition of hardmasks for vacuum gap formation

A method for forming a vacuum gap in a dielectric substrate comprising:

• depositing a self-assembled monolayer with a reactive head group that binds to copper onto a dielectric substrate with copper features;
• forming a hardmask on the dielectric substrate by area selective deposition of zinc oxide onto the dielectric substrate, wherein (i) due to the self-assembled monolayer bound to the copper features, the hardmask material reaches, but does not touch the copper features, (ii) the copper features and the zinc oxide collectively form the hardmask, and (iii) the hardmask has gaps in areas located between the copper features and the selectively deposited zinc oxide;
• etching the dielectric substrate, wherein the etching forms trenches in the gaps defined by the hardmask and undercuts the hardmask at the trench opening resulting in trenches with depths that are greater than the trench opening widths;
• and
• depositing a non-conformal coating onto the dielectric substrate, wherein the non-conformal coating closes the trench openings to create vacuum gaps in the trenches.

A method for forming a vacuum gap in a dielectric substrate comprising:

• depositing a self-assembled monolayer with reactive head groups onto a dielectric substrate with metal features, wherein the reactive head groups bind to the metal features;
• forming a hardmask on the dielectric substrate by area selective deposition of a hardmask material onto the dielectric substrate, wherein (i) due to the self-assembled monolayer bound to the metal features, the hardmask material reaches, but does not touch the metal features, (ii) the metal features and the hardmask material collectively form the hardmask, and (iii) the hardmask has gaps in areas located between the metal features and the selectively deposited hardmask material;
• removing the self-assembled monolayer from the dielectric substrate;
• etching the dielectric substrate, wherein the etching forms trenches in the gaps defined by the hardmask and undercuts the hardmask at the trench opening resulting in trenches with depths that are greater than the trench opening widths;
• depositing a non-conformal coating onto the dielectric substrate, wherein the non-conformal coating closes the trench openings to create vacuum gaps in the trenches;
• and
• planarizing the dielectric substrate to form a smooth surface on the dielectric substrate.

A method for forming a vacuum gap in a dielectric substrate comprising:

• depositing a self-assembled monolayer with reactive head groups onto a dielectric substrate with metal features, wherein the reactive head groups bind to the metal features;
• forming a hardmask on the dielectric substrate by area selective deposition of a hardmask material onto the dielectric substrate, wherein (i) due to the self-assembled monolayer bound to the metal features, the hardmask material reaches, but does not touch the metal features, (ii) the metal features and the hardmask material collectively form the hardmask, and (iii) the hardmask has gaps in areas located between the metal features and the selectively deposited hardmask material;
• etching the dielectric substrate, wherein the etching forms trenches in the gaps defined by the hardmask and undercuts the hardmask at the trench opening resulting in trenches with depths that are greater than the trench opening widths, and further wherein the etching removes the self-assembled monolayer from the dielectric substrate;
• depositing a non-conformal coating onto the dielectric substrate, wherein the non-conformal coating closes the trench openings to create vacuum gaps in the trenches;
• and
• planarizing the dielectric substrate to form a smooth surface on the dielectric substrate.