Semiconductor Power Rail Structure With Sacrificial Trench Replacement
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Solution Overview
Problem
The semiconductor industry faces challenges in forming reliable semiconductor devices at increasingly smaller sizes due to the complexity and difficulty of fabrication processes as feature sizes continue to decrease, affecting production efficiency and costs.
Innovation Solution
The process involves forming FinFET structures with fins and gate all around (GAA) transistor structures using semiconductor layers with alternating materials for etching selectivity and oxidation rates, combined with epitaxial growth and patterning techniques like double-patterning or multi-patterning processes, to create channel structures and source/drain structures, and replacing sacrificial layers with conductive structures for improved device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes continue to decrease to increase functional density, then production efficiency improves and costs lower, but fabrication process complexity increases and manufacturing difficulty worsens
Solution Approach 1:
The fabrication process is divided into multiple distinct stages including forming first and second trenches at different depths, selective epitaxial growth in specific regions, and staged doping processes. This segmentation allows each step to be optimized independently, managing overall process complexity while enabling continued scaling for improved productivity
Solution Approach 2:
Sacrificial structures are formed in advance before the final device structure is complete. These preliminary structures guide subsequent processing steps and are removed later, allowing complex three-dimensional structures to be built systematically while maintaining manufacturing feasibility at smaller feature sizes
2Productivity
If feature sizes decrease to increase functional density, then more devices fit per chip area, but reliability of individual devices becomes harder to maintain
Solution Approach 1:
Different regions of the semiconductor structure receive different treatments: epitaxial growth is performed selectively in certain trenches while other regions undergo different processing. This local differentiation allows optimization of electrical properties in specific areas to maintain device reliability even as overall feature sizes decrease and functional density increases
Solution Approach 2:
Sacrificial structures serve as intermediary elements that enable the formation of complex three-dimensional structures. These temporary structures facilitate precise positioning and formation of active regions, ensuring proper device geometry and electrical characteristics are achieved at scaled dimensions
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 reliability and efficiency of semiconductor device fabrication by enabling precise control over fin structures and channel formation, improving current flow and reducing parasitic capacitance, thus addressing the challenges of scaling down while maintaining device quality and performance.
Implementation Method 1
forming FinFET structures with fins and gate all around (GAA) transistor structures using semiconductor layers with alternating materials for etching selectivity and oxidation rates, combined with epitaxial growth
Data Source
AI summary
A semiconductor device structure and a formation method are provided. The method includes forming a first fin structure and a second fin structure over a substrate. The method also includes partially removing the substrate to form a trench between the first fin structure and the second fin structure and forming a sacrificial structure to fill the trench. The method further includes forming an epitaxial structure on the first fin structure and forming a conductive contact over the epitaxial structure and the sacrificial structure. In addition, the method includes replacing the sacrificial structure with a conductive structure.