Method of processing a substrate and a device manufactured by using the method
A method of processing a substrate by omitting a photolithographic process is disclosed. The method includes forming at least one layer on a stepped structure having an upper surface, a lower surface, and a side surface that connects the upper surface to the lower surface, selectively densifying portions of the at least one layer respectively on the upper surface and the lower surface via asymmetric plasma application, and performing an isotropic etching process on the at least one layer. During the isotropic etching process, the portion of the at least one layer formed on the upper surface is separated from the portion of the at least one layer formed on the lower surface.
1. A method of processing a substrate, the method comprising:
forming a first layer on a stepped structure having an upper surface, a lower surface, and a side surface that connects the upper surface to the lower surface;
forming a second layer on the first layer, the second layer being formed of the same material as a material for the first layer; and
performing an isotropic etching process on the first layer and the second layer,
wherein, during the isotropic etching process, an etch rate of a portion of the second layer on the side surface is greater than an etch rate of portions of the second layer on the upper and lower surfaces, and
wherein the method further comprises selectively densifying the second layer.
2. The method of claim 1 , wherein the densifying is performed via an asymmetric plasma application.
3. The method of claim 1 , wherein the second layer is selectively densified through a post-plasma treatment after the forming the second layer.
4. The method of claim 1 , wherein the second layer is selectively densified during the forming the second layer.
5. The method of claim 4 , wherein a plasma is applied during the forming the second layer, and
wherein a directivity of the plasma is controlled to control a feature of the second layer according to positions of the stepped structure.
6. A method of processing a substrate, the method comprising:
forming a first layer on a stepped structure having an upper surface, a lower surface, and a side surface that connects the upper surface to the lower surface;
forming a second layer on the first layer, the second layer being formed of the same material as a material for the first layer; and
performing an isotropic etching process on the first layer and the second layer,
wherein, during the isotropic etching process, an etch rate of a portion of the second layer on the side surface is greater than an etch rate of portions of the second layer on the upper and lower surfaces, and
wherein a flow rate of a hydrogen-containing gas used in the forming of the second layer is less than a flow rate of a hydrogen-containing gas used in the forming of the first layer.
7. A method of processing a substrate, the method comprising:
forming a first layer on a stepped structure having an upper surface, a lower surface, and a side surface that connects the upper surface to the lower surface;
forming a second layer on the first layer, the second layer being formed of the same material as a material for the first layer; and
performing an isotropic etching process on the first layer and the second layer,
wherein, during the isotropic etching process, an etch rate of a portion of the second layer on the side surface is greater than an etch rate of portions of the second layer on the upper and lower surfaces, and
wherein a hydrogen content of the second layer is less than a hydrogen content of the first layer.
8. A method of processing a substrate, the method comprising:
forming at least one layer on a stepped structure having an upper surface, a lower surface, and a side surface that connects the upper surface to the lower surface,
wherein portions of the at least one layer respectively on the upper surface and the lower surface except for the side surface are selectively densified via an asymmetric plasma application.
9. The method of claim 8 , further comprising:
performing an isotropic etching process on the at least one layer,
wherein, during the isotropic etching process, the portion of the at least one layer formed on the upper surface is separated from the portion of the at least one layer formed on the lower surface.
10. The method of claim 8 , wherein the at least one layer is formed through a PEALD process using the asymmetric plasma application.
11. The method of claim 10 , wherein the PEALD process a cycle including source feeding, purging, reactant feeding, RF plasma, and purging, and
wherein the asymmetric plasma application is achieved by the RF plasma.
12. A method of processing a substrate, the method comprising:
a first SiN thin film deposition step to form a first silicon nitride layer on a stepped structure having an upper surface, a lower surface, and a side surface that connects the upper surface to the lower surface;
a second PEALD SiN thin film deposition step to form a second nitride layer on the first silicon nitride layer; and
a wet etching step after the second PEALD thin film deposition step,
wherein plasma having directivity is applied in the second PEALD SiN thin film deposition step.
13. The method of claim 12 , wherein a nitrogen content of the second silicon nitride layer is greater than a nitrogen content of the first silicon nitride layer.