Semiconductor Memory Device Trench Isolation for Floating Gate Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The manufacturing process of semiconductor memory devices faces challenges in enhancing yield due to issues such as curved edges in shallow trench isolation structures affecting the formation of floating gate electrodes, leading to reduced spacing between electrodes and potential short circuits.
Innovation Solution
A semiconductor active structure is formed in a trench penetrating through the isolation layer, avoiding the influence of edge shapes and allowing for improved alignment and spacing between floating gate electrodes, thereby enhancing manufacturing yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shallow trench isolation structure is formed in semiconductor material, then isolation between active regions is achieved, but curved edges are formed which affect subsequent floating gate electrode formation and reduce manufacturing yield
Solution Approach 1:
The isolation structure is segmented by introducing a trench that divides the continuous isolation layer into separate regions. This segmentation eliminates the curved edge problem at the isolation layer boundaries, providing straight-edged isolation regions that improve alignment precision for subsequent floating gate electrode formation and enhance manufacturing yield.
2Productivity
If memory miniaturization is pursued to achieve large-capacity and low-cost memory devices, then integration density is improved, but fabrication process complexity increases and manufacturing yield decreases
Solution Approach 1:
The trench is formed in advance during the isolation layer processing stage, before the floating gate electrode formation and subsequent fabrication steps. This preliminary action of creating the trench structure early in the process eliminates curved edge issues that would otherwise complicate later alignment-critical steps, thereby reducing overall fabrication process complexity while maintaining high integration density.
Data Source
AI summary
A semiconductor memory device includes a substrate, an isolation layer, a trench, a semiconductor active structure, and a floating gate electrode. The isolation layer is disposed on the substrate. The trench penetrates through the isolation layer and exposes a part of the substrate. The semiconductor active structure is disposed in the trench, and the floating gate electrode is disposed on the semiconductor active structure. A manufacturing method of the semiconductor memory device includes the following steps. The isolation layer is formed on the substrate. The trench is formed penetrating through the isolation layer and exposing a part of the substrate. The semiconductor active structure is formed in the trench. The floating gate electrode is formed on the semiconductor active structure.