GAA Nanostructure Stack With Stressor Overlap for Channel Reliability
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Solution Overview
Problem
The challenge of forming reliable semiconductor devices at smaller sizes is exacerbated by the increasing complexity of fabrication processes as feature sizes continue to decrease, making it difficult to achieve efficient and reliable manufacturing.
Innovation Solution
The formation of gate all around (GAA) transistor structures using nanostructures, which are patterned through photolithography and self-aligned processes, allowing for pitches smaller than traditional methods, combined with epitaxial and deposition processes to create a nanostructure stack over a fin, and the use of stressor structures to enhance channel properties.
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 reliability becomes difficult to achieve
Solution Approach 1:
The patent segments the fabrication process into distinct stages: forming mandrels with first pitch, depositing spacers, selectively removing portions, and forming final structures with second pitch. This segmentation allows complex patterning to be broken down into manageable steps, achieving smaller feature sizes while controlling process complexity through systematic decomposition.
Solution Approach 2:
The patent transitions from planar patterning to three-dimensional structures by forming vertical spacers and stacked configurations. The self-aligned spacer formation adds a vertical dimension to the patterning process, enabling smaller lateral features through vertical spacing while maintaining manufacturing control through conformal deposition processes.
2Productivity
If feature sizes continue to decrease to increase functional density, then more devices fit per chip area, but manufacturing reliability becomes more difficult to achieve
Solution Approach 1:
The spacer formation process is self-aligned to the mandrel structures, automatically positioning spacers at correct intervals without requiring additional alignment steps. This self-alignment mechanism ensures manufacturing reliability by using the deposited material itself as the positioning reference, eliminating the need for complex external alignment procedures.
Solution Approach 2:
The patent replaces mechanical alignment procedures with a deposition-based self-alignment process. Instead of mechanically positioning features through multiple lithography alignment steps, the conformal deposition of spacer material naturally aligns structures to the mandrel geometry, substituting mechanical precision requirements with material deposition control.
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 the fabrication of semiconductor devices with improved channel properties and enhanced reliability by utilizing nanostructures and stressor structures to provide compressive or tensile stress, thereby improving performance and efficiency in smaller device sizes.
Implementation Method 1
the use of stressor structures to enhance channel properties... providing compressive or tensile stress
Data Source
AI summary
A semiconductor device structure is provided. The semiconductor device structure includes a first nanostructure over a substrate and a second nanostructure over the first nanostructure. The first nanostructure is thicker than the second nanostructure. The semiconductor device structure also includes a gate stack wrapped around the first nanostructure and the second nanostructure. The semiconductor device structure further includes a stressor structure beside the first nanostructure and the second nanostructure. The stressor structure has a lightly doped layer and a heavily doped structure over the lightly doped layer, and the heavily doped structure laterally overlaps with the first nanostructure.