Semiconductor Trench Liner Uniformity via CMP
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Solution Overview
Problem
Conventional semiconductor processing techniques face challenges in achieving uniformity and charge balancing across device structures, particularly in high-power devices, due to the sensitivity of liner layers to downstream processes like plasma processing, leading to uneven charge distribution and potential breakdown in edge regions.
Innovation Solution
The method involves forming a liner layer along the sidewalls and surface of trenches in a semiconductor substrate, removing it using chemical-mechanical polishing, and reforming it to accommodate downstream processes, allowing for a tuned layer that ensures balanced charge distribution across both trench and planar regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liner layer is formed along sidewalls and surfaces of trenches in a semiconductor substrate, then charge balancing is improved, but the liner layer becomes sensitive to downstream plasma processes causing uneven charge distribution
Solution Approach 1:
The patent applies preliminary action by performing a first chemical-mechanical polishing (CMC) operation immediately after forming the liner layer to remove plasma-sensitive material before downstream plasma processes occur. This preemptive removal prevents the liner layer from being adversely affected by subsequent plasma processing, thereby maintaining uniform charge distribution and improving device reliability.
2Manufacturing precision
If the liner layer thickness is reduced to less than 5 nm, then manufacturing precision is improved, but the layer becomes more sensitive to removal processes
Solution Approach 1:
The patent replaces conventional mechanical polishing with a chemical-mechanical polishing (CMC) process. The CMC process uses chemical etchants to selectively remove the thin liner layer material while maintaining mechanical polishing benefits, enabling precise control of ultra-thin layer removal without the limitations of purely mechanical methods. This substitution allows uniform removal of sub-5nm liner layers with controlled thickness and minimal damage.
3Manufacturing precision
If chemical-mechanical polishing is used to remove dielectric material and liner, then manufacturing precision is improved, but additional process steps are required
Solution Approach 1:
The patent merges the removal of dielectric material and liner layer into a single chemical-mechanical polishing step. By combining these two removal functions into one CMC process, the patent achieves precise control over both material types while reducing the total number of separate process steps compared to using different removal methods for each material layer.
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 enables improved charge balancing and uniformity, reducing the likelihood of premature breakdown in edge regions and enhancing device performance by preemptively addressing the effects of downstream processing on the liner layer.
Implementation Method 1
Removing the dielectric material and the liner may include performing a chemical-mechanical polishing operation to remove the dielectric material from the first surface of the semiconductor substrate
Implementation Method 2
performing a plasma operation. Ions formed in the plasma operation may affect a charge of the layer of the liner across the first surface of the semiconductor substrate
Data Source
AI summary
Exemplary methods of forming a semiconductor structure may include forming a liner along sidewalls of a trench defined from a first surface of a semiconductor substrate. The liner may extend along the first surface of the semiconductor substrate. The methods may include filling the trench with a dielectric material. The methods may include removing the dielectric material and the liner from the first surface of the semiconductor substrate. The methods may include forming a layer of the liner across the first surface of the semiconductor substrate and the trench defined within the semiconductor substrate.