GAP FILL USING CARBON-BASED FILMS
Provided herein are methods of filling gaps using high density plasma chemical vapor deposition (HDP CVD). According to various implementations, carbon-containing films such as amorphous carbon and amorphous carbide films are deposited by HDP CVD into gaps on substrates to fill the gaps. The methods may involve using high hydrogen-content process gasses during HDP CVD deposition to provide bottom-up fill. Also provided are related apparatus.
1 . A method comprising:
introducing a process gas to a high density plasma chemical vapor deposition (HDP CVD) chamber that houses a substrate having a gap, wherein the process gas includes a hydrocarbon reactant and has a H:C ratio of at least 4:1; and
filling the gap with a carbon-based film by an HDP CVD reaction of the process gas.
2 . The method of claim 1 , wherein the gap is filled in a single deposition operation with no intervening etch operations.
3 . The method of claim 1 , wherein the carbon-based film is an amorphous carbon (a-C) film.
4 . The method of claim 1 , wherein the carbon-based film is an amorphous carbide film.
5 . The method of claim 4 , wherein the carbon-based film is a doped or undoped amorphous silicon carbide film.
6 . The method of claim 5 , wherein the process gas includes a silicon-containing reactant having a H:Si ratio of at least 4.
7 . The method of claim 1 , wherein the hydrocarbon reactant has a H:C ratio of at least 3:1.
8 . The method of claim 7 , wherein the hydrocarbon reactant has a H:C ratio of at least 4:1.
9 . The method of claim 1 , wherein the process gas includes molecular hydrogen (H 2 ).
10 . The method of claim 1 , further comprising generating a plasma including hydrogen radicals.
11 . The method of claim 1 , wherein the filling the gap comprises a hydrogen radical etch at the top of the gap during the HDP CVD reaction.
12 . The method of claim 1 , wherein filling the gap with a carbon-based film comprises two or more deposition stages and one or more intervening etch operations.
13 . The method of claim 12 , wherein the one or more intervening etch operations are hydrogen-based etches.
14 . An apparatus comprising:
a plasma generator;
chamber comprising a pedestal;
one or more inlets to the chamber; and
a controller comprising machine-readable instructions for:
inletting a process gas comprising a hydrocarbon reactant, wherein the process gas has a H:C ratio of at least 4:1; and
generating a high density plasma in the chamber to thereby fill a gap on a substrate in the chamber.
15 . The apparatus of claim 14 , wherein the hydrocarbon reactant has a H:C ratio of at least 3:1.
16 . The apparatus of claim 14 , wherein the hydrocarbon reactant has a H:C ratio of at least 4:1.
17 . The apparatus of claim 14 , wherein the process gas includes a silicon-containing reactant having a H:Si ratio of at least 4.
18 . The apparatus of claim 14 , wherein the process gas includes molecular hydrogen (H 2 ).