Semiconductor Memory Dam Structure for Density Transition
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Solution Overview
Problem
The increasing integration density in semiconductor devices leads to process difficulties and reduced production yield and reliability due to differences in pattern density between memory cell and peripheral regions, which can cause failures and short circuits.
Innovation Solution
Incorporating a dam structure and dummy landing pads in the intermediate region, extending in a specific direction, and spacing them apart to avoid vertical overlap with bit lines, along with a planarization process to manage pattern density differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If integration density is increased, then device functionality and speed are improved, but process failures and short circuits increase due to pattern density differences
Solution Approach 1:
The layout is divided into distinct regions (memory cell region, intermediate region, peripheral region) with different pattern densities. The intermediate region acts as a buffer zone that segments the high-density memory cell area from the low-density peripheral area, preventing direct interaction between patterns of different densities and reducing process failures.
Solution Approach 2:
The intermediate region serves as an intermediary zone between the memory cell region and peripheral region. It contains dummy patterns that mediate the transition between different pattern densities, providing a gradual transition rather than an abrupt change, thereby reducing stress on adjacent patterns and preventing short circuits.
2Adaptability or versatility
If pattern density differs between memory cell and peripheral regions, then device functionality is achieved, but manufacturing precision deteriorates
Solution Approach 1:
Different regions of the semiconductor device are assigned different pattern densities according to their functional requirements. The memory cell region has high pattern density for functionality, while the peripheral region has low pattern density for simplicity. The intermediate region provides a transition zone that maintains manufacturing precision by avoiding abrupt changes in pattern density.
3Area of stationary object
If dummy patterns are placed close to bit lines, then space utilization is improved, but short circuit risk increases
Solution Approach 1:
Dummy patterns are strategically positioned in the intermediate region with deliberate spacing from bit lines. This predetermined spacing acts as a cushioning zone that prevents direct contact between dummy patterns and bit lines, eliminating short circuit risks while still maintaining efficient space utilization in the overall device layout.
Data Source
AI summary
A semiconductor memory device includes a substrate including memory cell, peripheral, and intermediate regions; a device isolation pattern; a partitioning pattern; bit lines extending in a first direction to a boundary between the intermediate and peripheral regions; storage node contacts on the memory cell region and filling a lower portion of a space between bit lines; landing pads on the storage node contacts; dummy storage node contacts on the intermediate region and filling a lower portion of a space between bit lines; dummy landing pads on the dummy storage node contacts; and a dam structure on the intermediate region, extending in the first direction, and having a bar shape, wherein the dummy landing pads are spaced apart from an edge of the dam structure in a second direction, and the dummy storage node contacts are in contact with the partitioning pattern.