Methods for fabricating device features having small dimensions
View Patent ↗Methods for fabricating devices having small feature sizes are provided. In an exemplary embodiment, a method comprises forming a patterned first mask layer overlying a subject material layer and isotropically etching the patterned first mask layer. A second masking layer is deposited overlying the patterned first mask layer and the isotropically-etched patterned first mask layer is exposed. The isotropically-etched patterned first mask layer is removed and the subject material layer is etched to form a feature therein.
1. A method for fabricating a device, the method comprising the steps of:
forming a patterned first mask layer overlying a subject material layer;
isotropically etching the patterned first mask layer;
depositing a second masking layer overlying the isotropically-etched patterned first mask layer;
exposing the isotropically-etched patterned first mask layer;
removing the isotropically-etched patterned first mask layer; and
etching the subject material layer to form a feature within the subject material layer.
2. The method of claim 1 , wherein the step of forming a patterned first mask layer comprises the step of forming a pattered carbon-comprising layer having a hydrogen content in a range of about 0 to about 30%.
3. The method of claim 1 , wherein the step of forming a patterned first mask layer comprises the step of forming the patterned first mask layer by etching a first mask layer using a patterned photoresist as an etch mask.
4. The method of claim 1 , wherein the step of forming a patterned first mask layer overlying a subject material layer comprises the step of forming the patterned first mask layer overlying an insulating layer.
5. The method of claim 1 , wherein the step of forming a patterned first mask layer overlying a subject material layer comprises the step of forming the patterned first mask layer overlying a semiconductor material layer.
6. The method of claim 1 , wherein the step of forming a patterned first mask layer overlying a subject material layer comprises the step of forming the patterned first mask layer overlying a subject material layer that is disposed on a semiconductor substrate.
7. The method of claim 1 , wherein the step of exposing the isotropically-etched patterned first mask layer is performed after the step of depositing a second masking layer overlying the patterned first mask layer.
8. The method of claim 7 , wherein the step of exposing the isotropically-etched patterned first mask layer comprises the step of removing a portion of the second masking layer by chemical mechanical planarization or dry etching.
9. The method of claim 1 , further comprising the steps of:
removing the second masking layer; and
depositing a conductive material within the feature of the subject material layer.
10. The method of claim 1 , wherein the step of isotropically etching the patterned first mask layer comprises the step of forming a first mask element that has a dimension that is substantially equal to a dimension of the subsequently formed feature in the subject material layer.
11. A method for fabricating a semiconductor device having a feature with a predetermined dimension, the method comprising the steps of:
patterning a carbon-comprising layer that overlies a subject material layer to form a carbon-comprising structure overlying the subject material layer;
isotropically etching the carbon-comprising structure to form a carbon-comprising element that has a dimension that is about equal to the predetermined dimension;
depositing a hard masking layer overlying the carbon-comprising element and the subject material layer;
removing a portion of the hard masking layer to expose the carbon-comprising element;
removing the carbon-comprising element; and
etching the subject material layer to form the feature having a dimension that is substantially equal to the predetermined dimension.
12. The method of claim 11 , wherein the step of patterning a carbon-comprising layer that overlies a subject material layer to form a carbon-comprising structure overlying the subject material layer comprises the steps of:
depositing a photoresist overlying the carbon-comprising layer;
patterning the photoresist using photolithography;
etching the carbon-comprising layer using the patterned photoresist as an etch mask.
13. The method of claim 11 , wherein the step of patterning a carbon-comprising layer that overlies a subject material layer to form a carbon-comprising structure overlying the subject material layer comprises the step of depositing the carbon-comprising layer having a hydrogen content in a range of about 0 to about 30% overlying the subject material layer.
14. The method of claim 11 , wherein the step of patterning a carbon-comprising layer that overlies a subject material layer comprises the step of patterning a carbon-comprising layer that overlies an insulating layer.
15. The method of claim 11 , wherein the step of patterning a carbon-comprising layer that overlies a subject material layer comprises the step of patterning a carbon-comprising layer that overlies a subject material layer disposed on a semiconductor substrate.
16. The method of claim 11 , wherein the step of isotropically etching the carbon-comprising structure to form a carbon-comprising element comprises the step of isotropically etching the patterned carbon-comprising structure using an oxygen-based plasma.
17. The method of claim 11 , further comprising the step of depositing a conductive material in the feature.