Trench Dielectric Enlargement to Reduce Word Line Interference

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Solution Overview

Problem

As semiconductor technology advances to nanoscale, existing contact structures in memory devices face challenges in minimizing disturbance between word lines, leading to performance degradation due to electric field interference.

Innovation Solution

A dielectric structure with an enlargement portion at the bottom is implemented, surrounded by a passing word line, which reduces the electric field disturbance to adjacent active word lines by widening the bottom of the trench and forming a dielectric structure with a maximum width that is about 1 nm to 10 nm wider than the top, using a specific manufacturing method involving etching operations and sacrificial layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a conventional contact structure is used in nanoscale semiconductor devices, then the device size can be reduced, but electric field disturbance between word lines increases causing performance degradation

Engineering Contradiction:

Improvedevice sizeVSAvoidelectric field disturbance

Core Design Contradiction:

Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The dielectric structure is segmented into two distinct width portions: a first width portion at the top and a second width portion at the bottom. This segmentation allows the bottom portion to be wider for shielding electric field disturbance while the top portion remains narrower to maintain small device footprint and proper contact structure geometry.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The dielectric structure transitions from a uniform cylindrical shape to a tapered shape with varying width along its height. By introducing dimensional variation (wider bottom, narrower top), the structure achieves both electric field shielding and compact size requirements that cannot be satisfied with a uniform cross-section.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Object-affected harmful factors

If the bottom of the trench is widened to reduce electric field disturbance, then the shielding effect improves, but the manufacturing complexity increases

Engineering Contradiction:

Improveelectric field disturbanceVSAvoidmanufacturing process complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

A sacrificial layer is deposited at the bottom of the trench before forming the dielectric structure. This preliminary action creates a template that defines the wider bottom portion, allowing the complex tapered shape to be formed through standard deposition and etching processes rather than requiring complex lithography or multiple fabrication steps.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The sacrificial layer acts as an intermediary element during fabrication. It is temporarily present to define the desired wider bottom geometry, facilitates the formation of the tapered dielectric structure, and is subsequently removed. This intermediary approach simplifies the overall manufacturing process by breaking down the complex shape formation into standard process steps.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If a protection layer is formed along the sidewall of the trench, then the etching precision is improved, but the device complexity increases

Engineering Contradiction:

Improveetching precisionVSAvoidstructure complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The protection layer serves multiple functions simultaneously: it protects the trench sidewalls during etching operations to maintain precision, defines the boundary for the wider bottom portion through selective removal, and acts as a mask for subsequent processing steps. This multi-functionality justifies the additional structural element.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The protection layer is temporarily introduced during fabrication to enable precise etching and proper formation of the tapered dielectric structure. After serving its protective and definitional functions, it is selectively removed in a controlled manner, allowing the final structure to achieve the desired geometry without permanent complexity from the protection layer.

Inventive Principle:

Principle #34Discarding and recovering

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 dielectric structure effectively reduces the electric field caused by the passing word line, enhancing the performance of the semiconductor device by minimizing interference with adjacent active word lines.

Implementation Method 1

A first etching operation is performed by the hard mask layer to form a trench in the substrate

Methodology Applied

Scientific EffectEtching:

Implementation Method 2

forming the sacrificial layer at the bottom of the trench includes depositing a sacrificial material in the trench

Methodology Applied

Scientific EffectDeposition: Deposition (physical)

Data Source

PatentUS11805640B2Manufacturing method of a semiconductor device using a protect layer along a top sidewall of a trench to widen the bottom of the trench

Publication Date: 2023.10.31 NAN YA TECH

AI summary

A semiconductor device includes a substrate, a passing word line in the substrate, and a dielectric structure surrounding the passing word line. The dielectric structure has an enlargement portion at a bottom of the dielectric structure, and a maximum width of the enlargement portion of the dielectric structure is wider than a width of a top of the dielectric structure.