Patterning Process of a Semiconductor Structure with a Wet Strippable Middle Layer

Abstract

A lithography method is provided in accordance with some embodiments. The lithography method includes forming an under layer of a polymeric material on a substrate; forming a silicon-containing middle layer on the under layer, wherein the silicon-containing middle layer has a silicon concentration in weight percentage less than 20% and is wet strippable; forming a patterned photosensitive layer on the silicon-containing middle layer; performing a first etching process to transfer a pattern of the patterned photosensitive layer to the silicon-containing middle layer; performing a second etching process to transfer the pattern to the under layer; and performing a wet stripping process to the silicon-containing middle layer and the under layer.

Description

technical field [0001] The present invention relates to the field of semiconductors, and more particularly to a process for patterning semiconductor structures with wet-stripping intermediate layers. Background technique [0002] In the manufacture of integrated circuits (ICs), patterned photoresist layers are used to transfer small feature-sized design patterns from photomasks to wafers. Photoresists are light sensitive and can be patterned by photolithography processes. In addition, the photoresist layer provides resistance to etching or ion implantation, which further requires a sufficient thickness. As IC technology continues to evolve to smaller feature sizes (eg, down to 32nm, 28nm, 20nm, and lower), thicknesses have not scaled down accordingly due to resistance needs. Depths of focus sufficient to cover thicker photoresists will degrade imaging resolution. Multi-film photoresists were introduced to overcome the above challenges. However, the added material in mult...

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Problems solved by technology

However, the additional material in multi-film photoresists is difficult to remove, either damaging the substrate or leaving a residue

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