Buried Word Line DRAM Layout for Smaller Memory Cells
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Solution Overview
Problem
DRAM manufacturers face challenges in minimizing memory cell area due to reduced word line spacing, which affects the performance and miniaturization of integrated circuits.
Innovation Solution
A semiconductor device design featuring a buried word line within the substrate, with bit lines and capacitors on opposite sides, allowing for a common switch to control two transistors, reducing device size and enhancing driving current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If word line spacing is reduced to minimize memory cell area, then memory cell area is reduced, but manufacturing precision and reliability deteriorate
Solution Approach 1:
The patent moves the word line from the surface plane into the substrate depth, creating a three-dimensional buried word line structure. This vertical relocation allows surface word lines to be spaced farther apart while maintaining high storage density through vertical stacking of memory cells, thereby resolving the contradiction between minimizing area and maintaining manufacturing precision.
Solution Approach 2:
The patent divides the memory cell structure into multiple vertical layers with buried word lines at different depths within the substrate. This segmentation into stacked memory cells allows each layer to be independently formed with adequate spacing, improving manufacturing precision while achieving high density through vertical integration.
2Ease of manufacture
If conventional surface word line structure is used, then manufacturing is simpler, but device size and complexity increase
Solution Approach 1:
By relocating word lines to the substrate depth and forming them as buried structures, the patent enables vertical stacking of multiple memory cell layers. This three-dimensional architecture reduces the horizontal footprint of the device while the formation process integrates seamlessly with standard semiconductor manufacturing techniques, maintaining ease of manufacture.
Solution Approach 2:
The patent implements nested memory cell structures where multiple layers of memory cells are stacked vertically, with buried word lines embedded at different depths within the substrate. This nesting approach minimizes device footprint by utilizing vertical space efficiently while maintaining manufacturability through systematic layer-by-layer formation.
Data Source
AI summary
A semiconductor device and a method of manufacturing the same are provided. The semiconductor device includes a substrate, a first word line, a bit line, and a first capacitor. The substrate has a first surface and a second surface opposite to the first surface. The first word line is disposed within the substrate. The bit line is disposed on the first surface of the substrate. The first capacitor is disposed on the second surface of the substrate.