Semiconductor device having air gap and method for manufacturing the same

A method for manufacturing a semiconductor device, comprising:

• forming metal lines on a conductive interconnect structure disposed on a substrate, the metal lines being spaced apart from each other;
• forming hard masks on the metal lines, respectively;
• forming functionalized polymers on a lateral surface of a corresponding one of the metal lines, each of the functionalized polymers including a carbon-based polymer chain and a functional group that is selectively bonded to the lateral surface of the corresponding one of the metal lines, the functional group being represented by formula (A):
• wherein R1, R2, R3 are each independently a methoxy group, a thiol group, or a dihydrogen phosphate group with the proviso that at least one of R1, R2, and R3 is the methoxy group;
• removing the carbon-based polymer chain of an upper portion of the functionalized polymers to leave the carbon-based polymer chain of a remainder of the functionalized polymers so as to form recesses, each of which is formed between two corresponding ones of the metal lines;
• forming a dielectric layer to cover the hard masks and to fill the recesses;
• and
• removing the carbon-based polymer chain of the remainder of the functionalized polymers so as to form air gaps among the metal lines.

A method for manufacturing a semiconductor device, comprising:

• forming metal lines over a substrate, the metal lines being spaced apart from each other;
• forming functionalized polymers on a lateral surface of a corresponding one of the metal lines, each of the functionalized polymers including a carbon-based polymer chain and a functional group that is bonded to the lateral surface of the corresponding one of the metal lines, the functional group being represented by formula (A):
• wherein R1, R2, R3 are each independently a methoxy group, a thiol group, or a dihydrogen phosphate group with the proviso that at least one of R1, R2, and R3 is the methoxy group;
• removing the carbon-based polymer chain of an upper portion of the functionalized polymers to leave the carbon-based polymer chain of a remainder of the functionalized polymers so as to form recesses, each of which is formed between two corresponding ones of the metal lines;
• forming a dielectric layer to cover the metal lines and to fill the recesses;
• removing the carbon-based polymer chain of the remainder of the functionalized polymers so as to form air gaps among the metal lines;
• and
• forming an interconnect structure on the dielectric layer opposite to the substrate, the interconnect structure including an electrically conductive interconnect electrically connected to one of the metal lines.