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:
forming a pair of sacrificial pedestals on a layer to be etched;
forming a spacer layer over at least the pair of sacrificial pedestals;
removing the pair of sacrificial pedestals and a portion of the spacer layer to form pairs of sacrificial spacers, each of the pairs of sacrificial spacers having one sacrificial spacer closest to another sacrificial spacer of the other pair and defining a space between the one and the other sacrificial spacers;
filling the space between the one and the other sacrificial spacers; and
removing the sacrificial spacers to form first spacers used during etching of the layer to be etched.
2. The method of claim 1 wherein the spacers comprise silicon nitride.
3. The method of claim 1 wherein each of the sacrificial spacers are formed from one of two different types of materials.
4. The method of claim 1 further comprising when filling the space, forming second spacers along the sides of the sacrificial spacers.