Micron Technology Incorporated

Tony Schrock

Gurtej S Sandhu

Max F Hineman

Shane J Trapp

Jingyi Bai

Daniel A Steckert

Mirzafer K Abatchev

Aaron R Wilson

A method of high aspect ratio contact etching a substantially vertical contact hole in an oxide layer using a hard photoresist mask is described. The oxide layer is deposited on an underlying substrate. A plasma etching gas is formed from a carbon source gas. Dopants are mixed into the gas. The doped plasma etching gas etches a substantially vertical contact hole through the oxide layer by doping carbon chain polymers formed along the sidewalls of the contact holes during the etching process into a conductive state. The conductive state of the carbon chain polymers reduces the charge buildup along sidewalls to prevent twisting of the contact holes by bleeding off the charge and ensuring proper alignment with active area landing regions. The etching stops at the underlying substrate.

Method to reduce charge buildup during high aspect ratio contact etch

The invention includes methods of etching features into substrates. A plurality of hard mask layers is formed over material of a substrate to be etched. A feature pattern is formed in such layers. A feature is etched only partially into the substrate material using the hard mask layers with the feature pattern therein as a mask. After the partial etching, at least one of the hard mask layers is etched selectively relative to the substrate material and remaining of the hard mask layers. After etching at least one of the hard mask layers, the feature is further etched into the substrate material using at least an innermost of the hard mask layers as a mask. After the further etching, the innermost hard mask layer and any hard mask layers remaining thereover are removed from the substrate, and at least a portion of the feature is incorporated into an integrated circuit.

Methods of etching features into substrates

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Boise, ID, United States of America

Tony Schrock