Recessing Carbon-Doped Semiconductor Layers via Selective Etching
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Solution Overview
Problem
Current semiconductor fabrication techniques face challenges in depositing and etching material layers, particularly at 7 nanometers and below, due to limitations in existing deposition and etching methods, which result in undesirable height variations and reduced yield.
Innovation Solution
A method involving the provision of a carbon-doped material layer within a semiconductor structure, where carbon is partially removed to create a carbon-depleted region with enhanced etch properties, allowing for selective recessing of the layer using remote plasma and etching processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching processes are used on carbon-doped material layers, then the etching can proceed uniformly, but the etch rate is slow and height variations occur
Solution Approach 1:
The patent applies local quality by creating a carbon-depleted region within the carbon-doped material layer through selective carbon removal. This carbon-depleted region has different etch properties (higher etch rate) compared to the carbon-doped regions, enabling selective and accelerated etching in specific areas while maintaining control over the overall etching process to achieve uniform height across the wafer.
2Productivity
If carbon is completely removed from the material layer, then the etch rate increases, but the material integrity and structural stability are compromised
Solution Approach 1:
The patent applies partial action by selectively removing carbon from only a portion of the carbon-doped material layer to create a carbon-depleted region, rather than removing all carbon. This partial carbon removal achieves the desired increased etch rate in the carbon-depleted region while preserving the structural integrity and stability of the remaining carbon-doped material, thus maintaining material reliability.
3Ease of manufacture
If existing deposition techniques are used at 7 nanometers and below, then the process can be maintained, but undesirable height variations and reduced yield occur
Solution Approach 1:
The patent applies parameter changes by modifying the carbon concentration distribution within the material layer through selective carbon removal. By creating regions with different carbon concentrations (carbon-doped vs. carbon-depleted), the etch parameters are effectively changed, enabling precise height control and eliminating the height variations that occur with conventional uniform carbon-doped layers at 7 nanometers and below.
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 enhances the ability to recess carbon-doped isolation and dielectric layers, reducing pattern-loading effects and improving yield by controlling the etch rate and preventing material degradation, thus addressing the limitations of existing techniques.
Implementation Method 1
removing, in part, carbon from the carbon-doped material layer to obtain, at least in part, a carbon-depleted region
Implementation Method 2
recessing the carbon-depleted region of the carbon-doped material layer by an etching process, wherein the carbon-depleted region is recessed based upon, in part, the modified etch property thereof
Data Source
AI summary
Semiconductor structure and methods of fabrication thereof are provided which includes, for instance, providing a carbon-doped material layer within a recess of a semiconductor structure; removing, in part, carbon from the carbon-doped material layer to obtain, at least in part, a carbon-depleted region thereof, the carbon-depleted region having a modified etch property with an increased etch rate compared to an etch rate of the carbon-doped material layer; and recessing the carbon-depleted region of the carbon-doped material layer by an etching process, with the carbon-depleted region being recessed based upon, in part, the modified etch property of the carbon-depleted region.