Doped STI Profile Control for Uniform Semiconductor Isolation
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Solution Overview
Problem
The complexity of semiconductor manufacturing processes is increased due to the scaling down of semiconductor devices, leading to challenges in achieving uniformity and preventing fabrication defects in isolation structures.
Innovation Solution
The implementation of doped shallow trench isolation (STI) structures with a doped liner and fill layer, where the etching rates are modified through annealing to achieve substantially equal rates, resulting in improved uniformity and planar top surface profiles, which facilitate the formation of subsequent structures with reduced defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional isolation structures are used in scaled-down semiconductor devices, then manufacturing complexity increases, but uniformity and defect prevention in isolation structures deteriorate
Solution Approach 1:
The patent modifies the etching rates of the liner and fill layer through parameter changes (doping concentrations, annealing conditions) to achieve substantially equal etching rates. This resolves the uniformity issue by ensuring that both layers etch at the same rate, preventing profile deviations and improving the consistency of isolation structures in scaled-down devices.
Solution Approach 2:
The patent applies preliminary doping and annealing treatments to the liner and fill layer before the final etching process. By pre-modifying the etching rates through these preliminary actions, the subsequent etching process produces uniform isolation structures without requiring complex real-time control, thus improving manufacturing precision while managing process complexity.
2Manufacturing precision
If etching rates of liner and fill layer are not matched, then manufacturing process is simpler, but fabrication defects increase
Solution Approach 1:
The patent changes the physical and chemical parameters of the liner and fill layer through doping and annealing processes. By adjusting dopant concentrations and thermal treatment conditions, the etching rates of both layers are modified to be substantially equal, achieving profile uniformity without introducing excessive manufacturing complexity.
Solution Approach 2:
Instead of mechanically controlling etching rates through complex process parameters, the patent substitutes this with chemical modification of the materials themselves. By doping the liner and fill layer with specific elements and annealing them, the etching rates are inherently matched through material property changes rather than process control, simplifying the overall manufacturing approach.
3Manufacturing precision
If non-planar top surface profiles are formed, then deposition process is simpler, but subsequent structure formation quality deteriorates
Solution Approach 1:
The patent performs preliminary etching of the liner and fill layer to create a planar top surface profile before subsequent deposition processes. This preliminary action ensures that the foundation for subsequent structures is uniform and planar, which facilitates the formation of linear sidewall profiles in later steps without requiring complex deposition process adjustments.
Solution Approach 2:
The patent modifies the etching parameters and material composition to achieve planar top surface profiles. By controlling the etching rates and material properties, the resulting surface is planar, which naturally facilitates the formation of subsequent structures with linear sidewall profiles, reducing the need for additional corrective processes.
4Reliability
If isolation structures have defects, then manufacturing process is simpler, but current leakage paths increase
Solution Approach 1:
The patent modifies the material composition and structural parameters of the isolation structures through doping and annealing. By changing the dopant concentrations and thermal processing conditions, the isolation structures achieve better electrical isolation properties, preventing current leakage paths while maintaining reasonable structural complexity.
Solution Approach 2:
The patent uses plasma-based annealing and doping processes to modify the isolation structures. These pneumatic/plasma processes enable precise control over material properties and structural characteristics, improving electrical isolation reliability without requiring excessive structural complexity.
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
The doped STI structures enhance the formation of subsequent structures with improved linear sidewall profiles, reducing fabrication defects and preventing current leakage paths, thus improving the manufacturing process efficiency and device performance.
Implementation Method 1
performing a doping process to form a doped oxide liner and a doped oxide fill layer... performing a chemical mechanical polishing (CMP) process on the doped oxide liner, the doped oxide fill layer, and cladding layers to substantially coplanarize top surfaces
Data Source
AI summary
A semiconductor device with doped shallow trench isolation (STI) structures and a method of fabricating the same are disclosed. The method includes forming a fin structure on a substrate, forming a superlattice structure with first and second nanostructured layers arranged in an alternating configuration on the fin structure, depositing an oxide liner surrounding the superlattice structure and the fin structure in a first deposition process, forming a dopant source liner on the oxide liner, depositing an oxide fill layer on the dopant source liner in a second deposition process different from the first deposition process, performing a doping process to form a doped oxide liner and a doped oxide fill layer, removing portions of the doped oxide liner, the doped oxide fill layer, and the dopant source liner from sidewalls of the superlattice structure, and forming a gate structure on the fin structure and surrounding the first nanostructured layers.