Non-lithographic line pattern formation
A metal layer is deposited over an underlying material layer. The metal layer includes an elemental metal that can be converted into a dielectric metal-containing compound by plasma oxidation and/or nitridation. A hard mask portion is formed over the metal layer. Plasma oxidation or nitridation is performed to convert physically exposed surfaces of the metal layer into the dielectric metal-containing compound. The sequence of a surface pull back of the hard mask portion, trench etching, another surface pull back, and conversion of top surfaces into the dielectric metal-containing compound are repeated to form a line pattern having a spacing that is not limited by lithographic minimum dimensions.
1. A patterned structure comprising a patterned layer located on an underlying material layer, said patterned layer comprising:
a first stack comprising a first metal portion and a first dielectric metal-containing compound portion contacting a top surface of said first metal portion; and
a second stack comprising a second metal portion and a second dielectric metal-containing compound portion overlying at least a peripheral portion of said second metal portion, wherein said second dielectric metal-containing portion has a topmost surface that is coplanar with a topmost surface of said second metal portion of said second stack, and outer sidewalls of said second stack are laterally spaced from inner sidewalls of said first stack by a same distance throughout an entire periphery of said second stack.
2. The patterned structure of claim 1 , wherein an inner sub-portion of said second metal portion has a same thickness as a stack of said second dielectric metal-containing compound portion and said peripheral portion of said second metal portion.
3. The patterned structure of claim 2 , wherein said first stack has said same thickness throughout an entirety of said first stack.
4. The patterned structure of claim 1 , wherein said first metal portion and said second metal portion have a same metallic composition containing at least one metal, and said first dielectric metal-containing compound portion and said second dielectric metal-containing compound portion have a composition that differ from said same metallic composition by presence of a non-metallic element.
5. The patterned structure of claim 4 , wherein each of said at least one metal is selected from aluminum, tantalum, titanium, tungsten, hafnium, zirconium, chromium, copper, zinc, iron, cobalt, and nickel.
6. The patterned structure of claim 4 , wherein said non-metallic element is oxygen.
7. The patterned structure of claim 4 , wherein said non-metallic element is nitrogen.
8. The patterned structure of claim 1 , wherein said second dielectric metal-containing compound portion overlies an entirety of said second metal portion.
9. The patterned structure of claim 8 , wherein a topmost surface of said second metal portion contacts a bottom surface of said second dielectric metal-containing compound portion.
10. The patterned structure of claim 1 , wherein a topmost planar surface of said second dielectric metal-containing compound portion is located above a horizontal plane including an interface between said second metal portion and said second dielectric metal-containing compound portion.
11. The patterned structure of claim 1 , further comprising a trench located within said patterned layer, wherein said outer sidewalls of said second stack and said inner sidewalls of said first stack are sidewalls of said trench.
12. The patterned structure of claim 11 , wherein a bottom surface of said trench is a physically exposed portion of said underlying material layer.
13. The patterned structure of claim 11 , wherein said outer sidewalls of said second stack comprises a sidewall of said second metal portion and a sidewall of said second dielectric metal-containing compound portion.
14. A patterned structure comprising a patterned layer located on an underlying material layer, said patterned layer comprising:
a first stack comprising a first metal portion and a first dielectric metal-containing compound portion contacting a top surface of said first metal portion; and
a second stack comprising a second metal portion and a second dielectric metal-containing compound portion overlying only a peripheral portion of said second metal portion, wherein outer sidewalls of said second stack are laterally spaced from inner sidewalls of said first stack by a same distance throughout an entire periphery of said second stack.