Directional Dielectric Deposition for Uniform Semiconductor Cavities
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Solution Overview
Problem
Existing methods for forming air gaps in semiconductor devices, such as those used in BEOL and FEOL processing, often result in low-quality and non-uniform air gaps due to inadequate dielectric deposition techniques, leading to partial and inconsistent gaps.
Innovation Solution
A directional deposition process involving multiple angles of inclination for dielectric material delivery is employed to form dielectric bridges over trenches, ensuring no deposition occurs in the lower trench portions, thereby creating wider and more consistent air gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional dielectric deposition techniques are used to form air gaps, then the deposition process is simple, but the resulting air gaps are non-uniform and partial
Solution Approach 1:
The deposition process is divided into multiple sequential steps with different angles of inclination. The first deposition forms a dielectric layer at a first angle, and the second deposition forms another dielectric layer at a second angle, creating a segmented approach to achieve uniform air gaps that a single-step process cannot accomplish
Solution Approach 2:
The patent introduces angular dimensionality to the deposition process by varying the angle of inclination between depositions. Instead of a single vertical deposition, material is delivered at multiple angles (e.g., 30 degrees and 60 degrees relative to the substrate normal), adding rotational freedom to achieve uniform coverage and consistent air gap formation
2Manufacturing precision
If directional deposition at multiple angles is used to form dielectric bridges, then air gap uniformity is improved, but the deposition process complexity increases
Solution Approach 1:
The first dielectric layer is deposited at a specific angle before the second deposition step. This preliminary action creates a foundation structure that guides the subsequent deposition, ensuring that the final dielectric bridge achieves the desired uniformity and connectivity over the trenches
Solution Approach 2:
The patent systematically varies deposition parameters including angle of inclination, deposition rate, and material composition between steps. By changing these parameters in a controlled sequence, the process achieves high-quality cavity formation while managing the complexity through structured parameter optimization
3Reliability
If uniform dielectric deposition is achieved through multiple angles, then capacitance is reduced and programming speed is enhanced, but the manufacturing process becomes more complex
Solution Approach 1:
The multi-angle deposition creates locally optimized dielectric structures with specific properties in different regions. The varying angles produce different deposition rates and film densities at different locations, achieving local quality optimization that reduces capacitance and enhances programming speed in critical areas
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 reduces capacitance, enhances programming speed, and is less sensitive to structural variations, resulting in improved cavity formation for semiconductor devices like 3D NANDs.
Implementation Method 1
forming a dielectric atop the plurality of semiconductor structures by delivering a dielectric material at a non-zero angle of inclination relative to a normal extending perpendicular from a top surface of the plurality of semiconductor structures
Data Source
AI summary
Disclosed are approaches for forming semiconductor device cavities using directional dielectric deposition. One method may include providing a plurality of semiconductor structures and a plurality of trenches of a semiconductor device, and forming a dielectric atop the plurality of semiconductor structures by delivering a dielectric material at a non-zero angle of inclination relative to a normal extending perpendicular from a top surface of the plurality of semiconductor structures. The dielectric may be further formed by delivering the dielectric material at a second non-zero angle of inclination relative to the normal extending perpendicular from the top surface of the plurality of semiconductor structures.