Carbon Layer Atomic Etch With High-Energy Directional Ion Removal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing atomic layer etching processes for carbon containing layers are slow and lack directional ion flow, resulting in low aspect ratio features and poor selectivity due to the use of low bias voltages that prevent physical sputtering.
Innovation Solution
A cyclical process involving exposure to oxygen radicals followed by high-energy ion bombardment for less than 0.5 seconds, with controlled bias between 100 eV and 2000 eV, to modify and remove the carbon containing layer, combined with optional passivation to reduce sidewall undercutting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low bias voltage is used to prevent physical sputtering, then selectivity is improved, but etching speed deteriorates
Solution Approach 1:
The patent implements a cyclical process alternating between a modification step (with low bias voltage to prevent sputtering and maintain selectivity) and a removal step (with high bias voltage to enable fast removal). This periodic switching allows the system to achieve both high selectivity during modification and high etching speed during removal, resolving the contradiction between these two parameters.
Solution Approach 2:
The etching process is divided into distinct segments: a modification step using oxygen radicals at low bias voltage to selectively modify the carbon-containing layer, and a removal step using high-energy ions at high bias voltage to rapidly remove the modified material. This segmentation allows each step to be optimized for its specific function, achieving both selectivity and speed.
2Reliability
If low bias voltage is used to prevent physical sputtering, then selectivity is improved, but aspect ratio deteriorates
Solution Approach 1:
By periodically switching between low bias voltage (during modification) and high bias voltage (during removal), the process achieves directional ion flow during the removal step that enables high aspect ratio features, while maintaining selectivity during the modification step.
Solution Approach 2:
The process segments the etching into modification and removal steps, with the removal step using high bias voltage to provide directional ion flow for high aspect ratio, while the modification step uses low bias voltage to maintain selectivity.
3Reliability
If atomic layer etching removes a few atomic layers per cycle, then selectivity is improved, but etching speed deteriorates
Solution Approach 1:
The cyclical process alternates between a modification step that modifies a controlled amount of material and a removal step that rapidly removes the modified material. This periodic action allows selective modification followed by fast removal, resolving the speed-selectivity tradeoff.
Solution Approach 2:
The etching process is segmented into modification and removal phases. The modification step uses oxygen radicals to selectively modify the carbon-containing layer, and the removal step uses high-energy ion bombardment to rapidly remove the modified material, achieving both selectivity and high etching speed.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enhances etching speed and selectivity, achieving up to five times the etch rate of individual steps, with improved feature aspect ratios and reduced physical sputtering.
Implementation Method 1
exposing the carbon containing etch layer to oxygen radicals to modify part of the carbon containing etch layer
Implementation Method 2
oxygen radicals are absorbed into the carbon containing etch layer to form a modified part
Implementation Method 3
the bombardment ions remove the modified part of the carbon containing etch layer
Implementation Method 4
exposes the etch layer to bombardment ions with an energy greater than 100 eV
Data Source
AI summary
A method comprises a plurality of cycles, wherein each cycle, comprises exposing the carbon containing etch layer to oxygen radicals to modify part of the carbon containing etch layer. The carbon containing etch layer is exposed to bombardment ions with an energy greater than 100 eV for less than 0.5 seconds, wherein the bombardment ions remove the modified part of the carbon containing etch layer to form etched features.