Ion-Cured Insulating Layers for High Aspect Ratio Trench Isolation
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Solution Overview
Problem
High aspect ratio trench isolation regions in semiconductor devices face defects due to increased aspect ratios during insulating film deposition, leading to seam formation and internal stress, especially with HARP oxide films, which also exhibit high wet etching rates with hydro-fluoric acid, causing recessed surfaces and yield reduction.
Innovation Solution
The method involves forming trenches in a semiconductor substrate, filling them with an insulating layer, implanting curing ions such as nitrogen, phosphorus, or germanium at specific energies and doses to reduce atomic disorder, and annealing at high temperatures to increase atomic order and densify the insulating region, thereby reducing seam formation and wet etching rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If HARP oxide film is used to fill high aspect ratio trenches, then gap-filling characteristics are improved, but seams are formed in the material due to deposition process characteristics
Solution Approach 1:
The patent applies ion implantation (changing the physical/chemical state of the oxide film) and thermal annealing (changing temperature parameters) to modify the properties of the HARP oxide film. These parameter changes eliminate seams by densifying the film structure and improving atomic ordering, while preserving the excellent gap-filling characteristics achieved through the HARP deposition process.
2Manufacturing precision
If HARP oxide film is used, then gap-filling characteristics are improved, but wet etching rate with hydro-fluoric acid increases causing surface recession
Solution Approach 1:
Ion implantation and thermal annealing are used to change the density and chemical composition parameters of the HARP oxide film. These changes reduce the wet etching rate with hydro-fluoric acid by creating a more resistant film structure, thereby preventing excessive surface recession while maintaining the beneficial gap-filling properties.
3Reliability
If ion implantation and annealing are performed, then seam formation is reduced and atomic order increases, but process complexity increases
Solution Approach 1:
The patent combines ion implantation and thermal annealing into an integrated treatment process that simultaneously achieves seam reduction, atomic ordering, and etching rate control. By merging these functions into a coordinated sequence of steps, the overall process complexity is managed while achieving multiple quality improvements in the oxide film.
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 effectively reduces seam formation and internal stress, enhances the quality of trench isolation regions, and decreases the wet etching rate with hydro-fluoric acid, resulting in more stable and efficient integrated circuit fabrication.
Implementation Method 1
Curing ions are then implanted into the electrically insulating region at a sufficient energy and dose to reduce a degree of atomic order therein
Implementation Method 2
The electrically insulating region is then annealed at a sufficient temperature and for a sufficient duration to increase a degree of atomic order within the electrically insulating region
Data Source
AI summary
Methods of forming integrated circuit devices include forming a trench in a surface of semiconductor substrate and filling the trench with an electrically insulating region having a seam therein. The trench may be filled by depositing a sufficiently thick electrically insulating layer on sidewalls and a bottom of the trench. Curing ions are then implanted into the electrically insulating region at a sufficient energy and dose to reduce a degree of atomic order therein. The curing ions may be ones selected from a group consisting of nitrogen (N), phosphorus (P), boron (B), arsenic (As), carbon (C), argon (Ar), germanium (Ge), helium (He), neon (Ne) and xenon (Xe). These curing ions may be implanted at an energy of at least about 80 KeV and a dose of at least about 5×1014 ions/cm2. The electrically insulating region is then annealed at a sufficient temperature and for a sufficient duration to increase a degree of atomic order within the electrically insulating region.