Seam mitigation and integrated liner for gap fill
Methods of filling a gap with a dielectric material including using an inhibitor plasma during deposition. The inhibitor plasma increases a nucleation barrier of the deposited film. When the inhibitor plasma interacts with material in the feature, the material at the bottom of the feature receives less plasma treatment than material located closer to a top portion of the feature or in field. Deposition at the top of the feature is then selectively inhibited and deposition in lower portions of the feature proceeds with less inhibition or without being inhibited. As a result, bottom-up fill is enhanced, which can create a sloped profile that mitigates the seam effect and prevents void formation. In some embodiments, an underlying material at the top of the feature is protected using an integrated liner. In some embodiments, a hydrogen chemistry is used during gap fill to reduce seam formation.
1 . A method comprising:
providing a substrate having structure including a gap to be filled;
depositing a protective liner selectively at an upper portion of the structure such that it extends only partially into the gap, wherein the structure is a 3D NAND structure and the gap is formed by two stacks of the 3D NAND structure, each stack comprising multiple pairs of an oxide layer and a nitride layer and capped by a polysilicon layer, and wherein the protective liner protects the polysilicon layer; and
performing one or more cycles of:
(a) exposing the substrate to a plasma comprising halogen species to inhibit deposition on a portion of the gap;
(b) after (a), depositing dielectric material in the gap.
2 . The method of claim 1 , wherein the protective liner is a silicon-containing film.
3 . The method of claim 1 , wherein the protective liner is an oxide, nitride, or carbide.
4 . The method of claim 1 , wherein the protective liner is etched during (a).
5 . The method of claim 1 , wherein the plasma during (a) is generated from nitrogen trifluoride (NF 3 ) and the protective liner is a silicon nitride film.
6 . The method of claim 1 , wherein the protective liner is between 10 and 999 Angstroms thick.
7 . The method of claim 1 , wherein depositing a protective liner and the performing one or more cycles are performed in the same chamber.
8 . The method of claim 1 , wherein depositing the protective liner comprises a plasma enhanced atomic layer deposition (ALD) process.
9 . The method of claim 8 , wherein plasma power during the ALD process is lower than plasma power during (a).
10 . The method of claim 1 , wherein depositing the protective liner comprises a plasma enhanced chemical vapor deposition (PECVD) process.
11 . The method of claim 10 , wherein the protective liner is a silicon carbide liner deposited from silane.
12 . The method of claim 1 , wherein the protective liner is silicon nitride and the dielectric material is silicon-containing.
13 . A method comprising:
providing a substrate having structure including a gap to be filled, the gap lined with a protective liner that extends only partially into the gap; and
performing one or more cycles of:
(a) exposing the substrate to a plasma comprising halogen species to inhibit deposition on a portion of the gap;
(b) after (a), depositing dielectric material in the gap;
and further comprising depositing a second protective liner that extends only partially into the gap during the one or more cycles.
14 . The method of claim 13 , wherein the plasma during (a) is generated from nitrogen trifluoride (NF 3 ) and the protective liner is a silicon nitride film.
15 . The method of claim 13 , wherein the plasma during (a) is generated from nitrogen trifluoride (NF 3 ) and the protective liner is a silicon carbide film.
16 . The method of claim 13 , wherein the protective liner is silicon nitride and the dielectric material is silicon-containing.