Semiconductor device with air gap and method of fabricating the same
A method of fabricating a semiconductor device and a semiconductor device formed by the method. The method includes form a stack conductive structure by stacking a first conductive pattern and an insulation pattern over a substrate; forming a sacrificial pattern over sidewalls of the stack conductive structure; forming a second conductive pattern having a recessed surface lower than a top surface of the stack conductive structure; forming a sacrificial spacer to expose sidewalls of the insulation pattern by removing an upper portion of the sacrificial pattern; reducing a width of the exposed portion of the insulation patters; forming a capping spacer to cap the sidewalls of the insulation pattern having the reduced width over the sacrificial spacer; and forming an air gap between the first conductive pattern and the second conductive pattern by converting the sacrificial spacer to volatile byproducts.
1. A method for fabricating a semiconductor device, the method comprising:
forming, over a substrate, a plurality of bit line structures, each including a stacked bit line and a hard mask pattern;
forming an inter-layer insulation layer over the plurality of bit line structures;
forming, by etching the inter-layer insulation layer, a contact hole between the plurality of bit line structures;
forming a carbon-containing spacer on sidewalls, of the plurality of bit line structures, that define the contact hole;
forming a first plug in the contact hole to form a recess plug structure, including the carbon-containing spacer, wherein the carbon-containing spacer is located between the first plug and the sidewalls of the contact hole;
removing the carbon-containing spacer to expose sidewalls of the hard mask pattern;
reducing a thickness of the exposed sidewalls of the hard mask pattern;
forming a capping spacer to cap the carbon-containing spacer and the reduced thickness sidewalls of the hard mask pattern; and
forming an air gap between the bit line and the first plug by converting the carbon-containing spacer to a volatile form.
2. The method of claim 1 , further comprising:
forming a bit line spacer over the plurality of bit line structures; and
wherein the forming the carbon-containing spacer on the sidewalls of the bit line structures that define the contact hole further comprises:
forming the carbon-containing spacer over the bit line spacer.
3. The method of claim 2 , wherein the bit line spacer includes an insulation material having a density that is sufficiently high as to prevent the converted carbon-containing spacer from diffusing through the bit line spacer.
4. The method of claim 1 , wherein the carbon-containing spacer includes amorphous carbon.
5. The method of claim 1 , wherein the converting the carbon-containing spacer to a volatile form comprises:
volatilizing the carbon-containing spacer via an oxygen plasma treatment.
6. The method of claim 1 , wherein the capping spacer includes an insulation material having a density that is sufficiently low as to allow the converted carbon-containing spacer to diffuse through the capping spacer.