Fluorocarbon Etching Uniformity via Cyclic Plasma
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Solution Overview
Problem
Existing methods for etching semiconductor devices struggle to achieve uniformity and selectivity in forming wide and narrow features, as they are often dependent on feature geometry and aspect ratio, leading to variations in etching results.
Innovation Solution
A cyclical process involving ion bombardment to create activated sites, exposure to fluorocarbon molecules for self-limiting binding, and subsequent ion bombardment to initiate an etch reaction, ensuring uniform etching independent of feature geometry and aspect ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching methods are used, then etching can be performed on semiconductor layers, but uniformity and selectivity deteriorate due to dependence on feature geometry and aspect ratio
Solution Approach 1:
The patent applies periodic action by implementing a cyclical etching process that alternates between plasma activation phases and fluorocarbon deposition phases. This periodic cycling allows controlled creation of activated sites followed by selective fluorocarbon binding, achieving uniform etching independent of feature geometry or aspect ratio variations
Solution Approach 2:
The patent utilizes parameter changes by transitioning between different plasma states (activation vs. deposition modes) and controlling fluorocarbon molecule exposure timing. By dynamically adjusting plasma power, pressure, and gas flow parameters during cyclic operation, the process achieves aspect ratio independent etching with high uniformity across different feature dimensions
2Productivity
If plasma is continuously provided for etching, then etching speed increases, but selectivity and self-limiting binding capability are lost
Solution Approach 1:
The patent implements periodic action by extinguishing plasma between activation and deposition steps. This allows fluorocarbon molecules to selectively bind to activated sites without continuous plasma interference, maintaining self-limiting binding behavior while achieving efficient etching through repeated cycling
Solution Approach 2:
The patent applies preliminary action by creating activated sites through ion bombardment before introducing fluorocarbon molecules. This pre-activation ensures that fluorocarbon binding occurs only at specific activated locations, providing selective and self-limiting deposition that maintains reliability while enabling subsequent rapid etching
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 approach results in highly uniform and selective etching with minimal variations in within-wafer and wafer-to-wafer repeatability, achieving consistent results across different feature widths and aspect ratios.
Implementation Method 1
providing by creating a plasma an ion bombardment of the etch layer to create activated sites of surface radicals
Implementation Method 2
providing by creating a plasma an ion bombardment of the etch layer to create activated sites of surface radicals
Implementation Method 3
exposing the etch layer to a plurality of fluorocarbon containing molecules, which causes the fluorocarbon containing molecules to selectively bind to the activated sites, wherein the selective binding is self limiting
Implementation Method 4
providing an ion bombardment of the etch layer to initiate an etch reaction between the fluorocarbon containing molecules and the etch layer
Implementation Method 5
providing an ion bombardment of the etch layer to initiate an etch reaction between the fluorocarbon containing molecules and the etch layer, wherein the ion bombardment of the etch layer to initiate an etch reaction causes the formation of volatile etch products
Data Source
AI summary
A method for etching features into an etch layer disposed below a patterned mask is provided. At least three cycles are provided, where each cycle comprises providing an ion bombardment, by creating a plasma, of the etch layer to create activated sites of surface radicals in parts of the etch layer exposed by the patterned mask, extinguishing the plasma, exposing the etch layer to a plurality of fluorocarbon containing molecules, which causes the fluorocarbon containing molecules to selectively bind to the activated sites, wherein the selective binding is self limiting, and providing an ion bombardment of the etch layer to initiate an etch reaction between the fluorocarbon containing molecule and the etch layer, wherein the ion bombardment of the etch layer to initiate an etch reaction causes the formation of volatile etch products formed from the etch layer and the fluorocarbon containing molecule.