DRAM Trench Electrode Structure With Expanded Landing Pad Contact

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Solution Overview

Problem

The trench forming process in semiconductor devices, particularly in DRAM structures, faces challenges due to the high aspect ratio of trenches and the etching resistivity of nitride layers, leading to shrinkage issues and increased resistance between electrode layers and landing pads.

Innovation Solution

A semiconductor device structure and manufacturing method that includes a landing pad, multiple nitride and oxide layers, and a trench with an expanding portion through the nitride layer, where the electrode layer is deposited on the inner sidewall of the trench and the top surface of the nitride layer, enhancing contact area and reducing electrical resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a trench with high aspect ratio is formed through multiple nitride and oxide layers, then the trench depth and structural integrity are improved, but the etching resistivity of nitride layers causes shrinkage problems and increased resistance between electrode layer and landing pad

Engineering Contradiction:

Improvetrench depth and shape controlVSAvoidelectrical resistance between electrode layer and landing pad

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent divides the trench structure into multiple segments by forming expanding portions at specific depths within the nitride layers. This segmentation allows different regions of the trench to serve different functions: the upper portion maintains etching resistance while the expanding portion provides electrical contact pathways, effectively resolving the contradiction between trench integrity and electrical connectivity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a dimensional change by creating expanding portions that increase the trench width at specific levels. This transforms the traditional vertical trench into a multi-dimensional structure with varying cross-sectional areas, allowing the electrode layer to make contact with the landing pad through expanded contact regions while maintaining the overall high aspect ratio structure.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If the trench width is increased at the top to improve contact area, then electrical resistance is reduced, but the trench aspect ratio and etching precision are compromised

Engineering Contradiction:

Improveelectrical contact qualityVSAvoidtrench width control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by creating expanding portions only at specific locations within the trench structure, rather than uniformly increasing the trench width throughout. This allows the trench to maintain precise width control in regions where etching precision is critical while providing localized expansion areas that enhance electrical contact without compromising overall manufacturing precision.

Inventive Principle:

Principle #3Local quality

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

The proposed solution effectively increases the contact area between the electrode layer and the landing pad, thereby reducing the electrical resistance between them, and improves the overall electrical performance of the semiconductor device.

Implementation Method 1

depositing an electrode layer on the inner sidewall of the trench and the top surface of the third nitride layer

Methodology Applied

Scientific EffectPhysical Vapour Deposition: Physical Vapour Deposition

Implementation Method 2

depositing an electrode layer on the inner sidewall of the trench and the top surface of the third nitride layer

Methodology Applied

Scientific EffectChemical Vapour Deposition: Chemical Vapour Deposition

Implementation Method 3

isotropically etching the first nitride layer to form an expanding portion and increase an overall width of the expanding portion

Methodology Applied

Scientific EffectIsotropic Etching:

Data Source

PatentUS20250174490A1Semiconductor device and method of manufacturing the same

Publication Date: 2025.05.29 NAN YA TECH

AI summary

A semiconductor device includes a landing pad, a first nitride layer, a first oxide layer, a second nitride layer, a second oxide layer, a third nitride layer, and an electrode layer. The first nitride layer is disposed over the landing pad. The first oxide layer is disposed on the first nitride layer. The second nitride layer is disposed on the first oxide layer. The second oxide layer is disposed on the second nitride layer. The third nitride layer is disposed on the second oxide layer. A trench runs through the third nitride layer, the second oxide layer, the second nitride layer, the first oxide layer, and the first nitride layer. The trench further has an expanding portion through the first nitride layer. The electrode layer is disposed on an inner sidewall of the trench and a top surface of the third nitride layer.