Method for pitch split patterning using sidewall image transfer
A method of forming a device includes forming a hard mask layer over an underlying layer of a substrate, forming an anti-reflective coating layer over the hard mask layer, forming a patterned resist layer over the anti-reflective coating layer, and forming a mandrel including the anti-reflective coating layer by patterning the anti-reflective coating layer using the patterned resist layer as an etch mask. The method includes forming a sidewall spacer on the mandrel including the anti-reflective coating layer, forming a freestanding spacer on the hard mask layer by removing the mandrel from the anti-reflective coating layer, and using the freestanding spacer as an etch mask, patterning the underlying layer of the substrate.
1. A method of patterning a substrate, the method comprising:
depositing an anti-reflective coating layer on a layer stack on a substrate;
depositing a layer of photoresist on the substrate subsequent to depositing the anti-reflective coating layer;
treating the anti-reflective coating layer with a flux of ballistic electrons prior to depositing the layer of photoresist;
forming a latent pattern within the layer of photoresist by exposing the layer of photoresist to a pattern of actinic radiation;
developing the layer of photoresist resulting in a relief pattern that includes mandrels;
transferring the relief pattern into the anti-reflective coating layer using a directional etch process, the anti-reflective coating layer resulting in the relief pattern that includes mandrels;
removing the layer of photoresist from the substrate;
forming sidewall spacers on mandrels formed from the anti-reflective coating layer;
removing the mandrels formed from the anti-reflective coating layer, while leaving the sidewall spacers on the substrate; and
transferring a pattern defined by the sidewall spacers into one or more underlying layers.
2. The method of claim 1 , further comprising depositing a protective film on a top surface of the anti-reflective coating layer prior to depositing the layer of photoresist.
3. The method of claim 2 , wherein the protective film is deposited via atomic layer deposition.
4. The method of claim 2 , wherein the protective film is deposited via chemical vapor deposition.
5. The method of claim 2 , wherein the protective film is deposited via sputter deposition.
6. The method of claim 2 , wherein the protective film is between one nanometer and five nanometers thick.
7. The method of claim 2 , wherein the protective film is a layer of silicon oxide.
8. The method of claim 1 , further comprising cross-linking material of the anti-reflective coating layer prior to depositing the layer of photoresist.
9. The method of claim 8 , further comprising depositing a protective film on a top surface of the anti-reflective coating layer prior to depositing the layer of photoresist.
10. The method of claim 1 , further comprising hardening material of the anti-reflective coating layer prior to depositing the layer of photoresist.
11. The method of claim 10 further comprising depositing a protective film on a top surface of the anti-reflective coating layer prior to depositing the layer of photoresist.
12. A method of forming a device, the method comprising:
forming a hard mask layer over an underlying layer of a substrate;
forming an anti-reflective coating layer over the hard mask layer;
forming a patterned resist layer over the anti-reflective coating layer;
cross-linking material of the anti-reflective coating layer prior to forming the patterned resist layer;
forming a mandrel comprising the anti-reflective coating layer by patterning the anti-reflective coating layer using the patterned resist layer as an etch mask;
forming a sidewall spacer on the mandrel comprising the anti-reflective coating layer;
forming a freestanding spacer on the hard mask layer by removing the mandrel from the anti-reflective coating layer; and
using the freestanding spacer as an etch mask, patterning the underlying layer of the substrate.
13. The method of claim 12 , further comprising, forming a protective film over the anti-reflective coating layer prior to forming the patterned resist layer by direct current superposition.
14. The method of claim 12 , further comprising forming a protective film over the anti-reflective coating layer by a coating process, spin-coating process, an atomic layer deposition process, a chemical vapor deposition process, or a sputter deposition process.
15. The method of claim 12 , wherein forming the mandrel further comprises depositing a protective film over the anti-reflective coating layer and patterning the protective film using the patterned resist layer as the etch mask.
16. A method of forming a device, the method comprising:
forming a hard mask layer over a substrate;
forming an anti-reflective coating layer over the hard mask layer;
forming a protective film over the anti-reflective coating layer by direct current superposition;
forming a patterned resist layer over the anti-reflective coating layer;
forming a mandrel comprising the anti-reflective coating layer by patterning the anti-reflective coating layer using the patterned resist layer as an etch mask, wherein forming the mandrel comprises patterning the protective film using the patterned resist layer as the etch mask;
forming a sidewall spacer on the mandrel comprising the anti-reflective coating layer;
forming a freestanding spacer on the hard mask layer by removing the mandrel from the anti-reflective coating layer; and
transferring a pattern defined by the freestanding spacer into an underlying layer of the substrate.
17. The method of claim 16 , wherein forming the protective film over the anti-reflective coating layer by direct current superposition comprises exposing the anti-reflective coating layer to an electron beam.