Patterning material including carbon-containing layer andmethod for semiconductor device fabrication

A method of forming a semiconductor structure, the method comprising:

• forming a stack over a target layer, wherein the forming the stack includes:
• depositing a first layer having a composition including at least 50 atomic percentage carbon over the target layer;
• depositing a second layer of amorphous silicon directly on the first layer;
• and
• depositing a photosensitive layer on the second layer;
• patterning the stack, wherein patterning the stack includes:
• performing a first etching process to reduce a height of the photosensitive layer and etch a portion of the second layer to provide an exposed top surface of the second layer, the exposed top surface of the second layer being rounded in a cross-sectional view;
• after the first etching process, performing a second etching process selective to the second layer of amorphous silicon, wherein the second etching process exposes a top surface of the first layer and wherein the performing the second etching process provides tapered sidewalls of the second layer of amorphous silicon;
• and
• performing a third etching process after the second etching process, wherein after the third etching process, the photosensitive layer is absent and a first height of the second layer over a second height of the first layer remains.

A method comprising:

• providing a first layer over a substrate, wherein the first layer has a first pattern including a first opening and a second opening, the second opening spaced a first distance in a first direction from the first opening in a top view;
• depositing a first patterning stack over the first layer having the first pattern, wherein the depositing the first patterning stack includes forming:
• a carbon-containing layer on the first layer having the first pattern, wherein the carbon-containing layer includes at least 50 atomic percentage carbon;
• a silicon-containing layer on the carbon-containing layer;
• and
• a patterned photoresist layer disposed over the silicon-containing layer, wherein the patterned photoresist layer defines a second pattern of a third opening and a fourth opening;
• etching the first layer using the first patterning stack as a mask during the etching to provide a patterned first layer having a pattern defined at least in part by the second pattern;
• depositing spacer elements on sidewalls of the patterned first layer;
• depositing a second patterning stack over the patterned first layer having spacer elements on sidewalls, wherein the depositing the second patterning stack includes forming:
• another carbon-containing layer;
• another silicon-containing layer on the another carbon-containing layer;
• and
• another patterned photoresist layer disposed over the another silicon-containing layer, wherein the another patterned photoresist layer defines a third pattern;
• etching the first layer using the second patterning stack as a mask while removing a portion of the first layer between the spacer elements.