Method for achieving very small feature size in semiconductor device by undertaking silicide sidewall growth and etching

摘要

In the present method of fabricating a semiconductor device, initially, a semiconductor substrate is provided. An oxide layer is provided on and in contact with the substrate, and a polysilicon layer is provided on and in contact with the oxide layer. A layer of photoresist is provided on the polysilicon layer, and the photoresist is patterned to provide a photoresist body, which is used as a mask to etch away polysilicon and oxide, forming a polysilicon element thereunder. The photoresist body is then removed. A nickel layer is provided on the resulting structure, and a reaction step is undertaken to provide that nickel diffuses into the exposed top and side portions of the polysilicon body, forming nickel silicide. After the reaction step, the remaining nickel is removed, and a chemical-mechanical polishing step is undertaken to remove nickel silicide so that a pair of nickel silicide bodies remain, separated by polysilicon. Using the nickel silicide bodies as masks, the polysilicon and oxide thereunder are etched away.

主权项

1. A method of fabricating an electronic device comprising:
providing a structure over an insulating layer and a substrate, the structure comprising a first body comprising a polysilicon and a second body comprising polysilicon reacted with at least some nickel from a nickel layer disposed over the first body, the second body comprising first, second, and third portions, the first portion being disposed between the second and third portions; removing the first portion of the second body, with at least a part of the second and third portions of the second body remaining; and removing an area of the first body using the second and third portions of the second body as a mask over a remaining area of the first body, wherein a side surface of the second portion is vertically aligned with a side surface of the first body and a side surface of the third portion is vertically aligned with an opposite side surface of the first body, further wherein a bottom surface of each of the second portion and the third portion is lower than a bottom surface of the first portion.