Nonvolatile Memory Outer Insulating Film Thickness Variation
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Solution Overview
Problem
Existing nonvolatile semiconductor memory devices face challenges in maintaining uniform electric fields across varying through hole diameters, leading to inefficiencies in memory cell operations, particularly during erase operations due to differences in curvature and insulating film thickness.
Innovation Solution
The nonvolatile semiconductor memory device employs a stacked structure with varying thicknesses of outer insulating films to compensate for non-uniform electric fields by adjusting the thickness of the outer insulating film in regions with different through hole diameters, ensuring equal electric fields across the inner and outer insulating films, thereby optimizing memory cell performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If insulating films are formed with uniform thickness in through holes of varying diameters, then manufacturing process is simplified, but electric field uniformity deteriorates
Solution Approach 1:
The patent applies local quality by making the outer insulating film thickness vary according to the local through hole diameter. Specifically, the outer insulating film is formed to be thicker in regions with larger through hole diameters and thinner in regions with smaller diameters, thereby compensating for the curvature differences and achieving uniform electric fields across different regions.
Solution Approach 2:
The patent changes the thickness parameter of the outer insulating film to compensate for variations in through hole diameter. By adjusting the film thickness parameter locally, the invention achieves uniform electric field distribution despite the varying geometries of the through holes.
2Manufacturing precision
If outer insulating film thickness is increased to compensate for larger through hole diameters, then electric field uniformity is improved, but device structure complexity increases
Solution Approach 1:
The patent introduces local quality variations in the outer insulating film thickness to compensate for the varying curvatures of through holes with different diameters. By making the film thicker in regions with larger diameters and thinner in regions with smaller diameters, uniform electric fields are achieved across the device structure.
Solution Approach 2:
The invention changes the thickness parameter of the outer insulating film locally to compensate for geometric variations. This parameter adjustment allows the device to maintain uniform electric field distribution while accommodating through holes of varying sizes.
Data Source
AI summary
According to one embodiment, a nonvolatile semiconductor memory device includes a stacked structure, a semiconductor pillar, a memory layer and an outer insulating film. The stacked structure includes a plurality of electrode films and a plurality of interelectrode insulating films alternately stacked in a first direction. The semiconductor pillar pierces the stacked structure in the first direction. The memory layer is provided between the electrode films and the semiconductor pillar. The outer insulating film is provided between the electrode films and the memory layer. The device includes a first region and a second region. An outer diameter of the outer insulating film along a second direction perpendicular to the first direction in the first region is larger than that in the second region. A thickness of the outer insulating film along the second direction in the first region is thicker than that in the second region.