Sublithographic Kelvin structure patterned with DSA
In one aspect, a DSA-based method for forming a Kelvin-testable structure includes the following steps. A guide pattern is formed on a substrate which defines i) multiple pad regions of the Kelvin-testable structure and ii) a region interconnecting two of the pad regions on the substrate. A self-assembly material is deposited onto the substrate and is annealed at a temperature/duration sufficient to cause it to undergo self-assembly to form a self-assembled pattern on the substrate, wherein the self-assembly is directed by the guide pattern such that the self-assembled material in the region interconnecting the two pad regions forms multiple straight lines. A pattern of the self-assembled material is transferred to the substrate forming multiple lines in the substrate, wherein the pattern of the self-assembled material is configured such that only a given one of the lines is a continuous line between the two pad regions on the substrate.
1. A method for forming a Kelvin-testable structure, the method comprising the steps of:
forming a guide pattern on a substrate, wherein the guide pattern defines i) multiple pad regions of the Kelvin-testable structure and ii) a line region interconnecting two of the pad regions on the substrate;
depositing a self-assembly material onto the substrate within the guide pattern;
annealing the self-assembly material at a temperature and for a duration sufficient to cause the self-assembly material to undergo self-assembly to form a self-assembled pattern on the substrate, wherein the self-assembly is directed by the guide pattern such that i) the self-assembled material in the line region interconnecting the two pad regions forms multiple straight lines, and ii) the guide pattern terminates one or more of the lines selective to neighboring lines; and
transferring a pattern of the self-assembled material in the line region interconnecting the two pad regions to the substrate forming multiple lines in the substrate, wherein the pattern of the self-assembled material is configured such that only a single given one of the lines is a continuous line between the two pad regions on the substrate with all other lines being discontinuous lines that do not connect to one of the pad regions and thus, while nested in the other lines, the single given line is an only continuous line between two of the pad regions on the substrate.
2. The method of claim 1 , further comprising the steps of:
removing the self-assembled material from the pad regions; and
filling the pad regions with an electrically conductive material to form pads on the substrate, wherein the pads are in contact with the continuous line between the two pad regions.
3. The method of claim 2 , wherein each of the pad regions defines two pads of the Kelvin-testable structure such that when the pad regions are filled with the electrically conductive material two of the pads are formed in contact with a first end of the continuous line between the two pad regions and two of the pads are formed in contact with a second end of the continuous line between the two pad regions.
4. The method of claim 1 , wherein the lines are formed in the substrate at a pitch of from about 10 nanometers to about 75 nanometers.
5. The method of claim 1 , wherein the pattern of the self-assembled material is configured such that an end of each of the lines, other than the continuous line between the two pad regions, is cut off before reaching one of the two pad regions.
6. The method of claim 1 , wherein the substrate comprises a dielectric layer.
7. The method of claim 1 , wherein the guide pattern is formed by patterning a surface of the substrate.
8. The method of claim 1 , wherein the guide pattern is formed in a layer deposited onto the substrate.
9. The method of claim 1 , wherein the self-assembly material comprises a block copolymer.
10. The method of claim 9 , wherein the block copolymer comprises a random copolymer of polystyrene (PS) and poly(methyl methacrylate) or a PS-block-PMMA copolymer (PS-b-PMMA).
11. The method of claim 1 , wherein the self-assembly material is annealed at a temperature of from about 190° C. to about 250° C.
12. The method of claim 1 , wherein the self-assembly material is annealed for a duration of from about 2 minutes to about 30 minutes.