Pitch reduction technology using alternating spacer depositions during the formation of a semiconductor device and systems including same
A method for patterning a layer increases the density of features formed over an initial patterning layer using a series of self-aligned spacers. A layer to be etched is provided, then an initial sacrificial patterning layer, for example formed using optical lithography, is formed over the layer to be etched. Depending on the embodiment, the patterning layer may be trimmed, then a series of spacer layers formed and etched. The number of spacer layers and their target dimensions depends on the desired increase in feature density. An in-process semiconductor device and electronic system is also described.
1. A method used during fabrication of a semiconductor device, the method comprising:
providing a first layer to be etched;
forming a first spacer material over the first layer to be etched;
etching the first spacer material to form a second layer to be etched;
forming a second spacer material over the second layer to be etched;
etching the second spacer material to form physically separated groups of spacers, each of the groups comprising five spacers physically contacting and aligned next to one another; and
etching the first layer to be etched using at least three of the spacers of the group as a pattern.
2. The method of claim 1 further comprising forming at least a portion of the spacer materials from photoresist.
3. The method of claim 1 further comprising forming at least a portion of the spacer materials from a material selected from the group consisting of transparent carbon, multilayer resist, and bilayer resist.
4. The method of claim 1 wherein the forming the spacer materials and the etching of the spacer materials is performed in a series of deposition and removal steps.
5. The method of claim 4 wherein a first step in the series comprises depositing the first spacer material upon the first layer to be etched.
6. The method of claim 5 wherein a second step in the series comprises removing at least some of the first spacer material to form a first group of spacers.
7. The method of claim 6 wherein a third step in the series comprises depositing a second spacer material upon at least a portion of the first group of spacers.