Layered Isolation Regions for Thermally Stable Active Regions

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Solution Overview

Problem

As semiconductor devices become more highly integrated, the reduction in active region widths leads to an increase in defects due to inadequate isolation techniques, particularly with shallow trench isolation (STI) methods.

Innovation Solution

The semiconductor device incorporates isolation regions formed of materials with different thermal degradation characteristics, including a first insulating material and a second insulating material with distinct properties, such as etch selectivity and density, to effectively define and protect active regions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If shallow trench isolation (STI) is used to define active regions, then active regions can be defined with standard isolation techniques, but thermal degradation and defects such as cracks occur in the active regions due to inadequate isolation

Engineering Contradiction:

Improveactive region integrityVSAvoidthermal degradation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The isolation region is divided into multiple segments with different insulating materials: a first insulating material layer and a second insulating material layer with different thermal expansion coefficients. This segmentation allows each layer to handle different aspects of thermal stress, preventing crack propagation and reducing thermal degradation in the active region.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The isolation region uses a composite structure combining two different insulating materials. The first insulating material provides baseline isolation, while the second insulating material with different thermal properties provides enhanced thermal stress management. This composite approach resolves the contradiction by maintaining isolation effectiveness while reducing thermal degradation harm.

Inventive Principle:

Principle #40Composite materials

2Productivity

If active region widths are reduced for high integration, then device integration density increases, but defects in active regions increase due to inadequate isolation

Engineering Contradiction:

Improveintegration densityVSAvoiddefect rate

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The isolation structure implements local quality by using different insulating materials at different locations within the isolation region. The first insulating material is used in the primary isolation area, while the second insulating material with different thermal properties is used in specific zones to provide enhanced protection against thermal degradation, thereby reducing defects in narrow active regions.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The dual-layer insulating material structure provides beforehand cushioning by pre-positioning materials with different thermal expansion coefficients to absorb and distribute thermal stresses before they can cause defects. This preventive measure allows active regions to be narrowed for high integration while maintaining reliability by cushioning against thermal-induced defects.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Ease of manufacture

If a single insulating material is used in the isolation region, then the structure is simple and easy to manufacture, but thermal degradation occurs due to uniform thermal expansion characteristics

Engineering Contradiction:

Improveisolation structure fabricationVSAvoidthermal stability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The invention changes the thermal parameters of the isolation region by introducing a second insulating material with different thermal expansion coefficient and density. This parameter change allows the isolation structure to better manage thermal stresses while maintaining manufacturability through established semiconductor fabrication processes for multi-layer dielectric structures.

Inventive Principle:

Principle #35Parameter changes

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

This approach reduces thermal degradation and prevents defects like cracks in active regions, enhancing the reliability and performance of semiconductor devices by using a layered isolation structure with specific material properties.

Implementation Method 1

isolation regions formed of materials having different thermal degeneration characteristics

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

reduces thermal degradation and prevents defects like cracks in active regions

Methodology Applied

Scientific EffectThermal stress: Thermal Shock

Data Source

PatentUS11830911B2Semiconductor device including isolation regions

Publication Date: 2023.11.28 SAMSUNG ELECTRONICS CO LTD

AI summary

A semiconductor device including a device isolation region is provided. The semiconductor device includes first active regions disposed on a substrate, and an isolation region between the active regions. The isolation region includes a first portion formed of a first insulating material, and a second portion formed of a second insulating material, having different characteristics from those of the first insulating material. The first portion is closer to the first active regions than the second portion. The second portion has a bottom surface having a height different from that of a bottom surface of the first portion.