Shallow Trench Isolation Layers With Rounded Corners for Reliability

Solution Overview

Problem

Conventional shallow trench isolation structures face challenges in reducing point discharge and improving reliability.

Innovation Solution

A shallow trench isolation structure is designed with a substrate, trenches, and sequentially stacked dielectric layers, featuring a fillet curve edge corner and additional dielectric layers to reduce point discharge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional shallow trench isolation structure is used, then manufacturing process is simple, but point discharge occurs and reliability is reduced

Engineering Contradiction:

Improvereliability of shallow trench isolation structureVSAvoidcomplexity of isolation structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The isolation structure is segmented into multiple dielectric layers (first dielectric layer, second dielectric layer, third dielectric layer) with different materials and functions. Each layer serves specific purposes: the first dielectric layer provides isolation, the second dielectric layer reduces point discharge, and the third dielectric layer provides additional protection. This segmentation allows the structure to address reliability issues while maintaining manageable complexity through functional division.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs composite materials by combining multiple dielectric layers with different properties. The first dielectric layer, second dielectric layer, and third dielectric layer are made of different materials that complement each other's characteristics. This composite approach enables the structure to simultaneously achieve good isolation performance, reduced point discharge, and improved reliability, resolving the contradiction between reliability enhancement and structural complexity.

Inventive Principle:

Principle #40Composite materials

2Reliability

If sharp corner at trench edge is used, then manufacturing is easier, but point discharge increases and reliability decreases

Engineering Contradiction:

Improvereliability of shallow trench isolation structureVSAvoidease of forming trench structure

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies curvature by forming a rounded corner at the intersection of the trench edge and substrate surface, replacing the conventional sharp corner. This rounded corner geometry eliminates the point discharge phenomenon that occurs at sharp edges, thereby improving reliability. The curvature is achieved through controlled processing steps that form a smooth transition, balancing manufacturing feasibility with reliability enhancement.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Reliability

If single dielectric layer is used, then structure is simple, but isolation performance and reliability are insufficient

Engineering Contradiction:

Improvereliability of shallow trench isolation structureVSAvoidcomplexity of dielectric layering

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The isolation structure is segmented into multiple dielectric layers (first dielectric layer, second dielectric layer, third dielectric layer) with different materials and functions. Each layer serves specific purposes: the first dielectric layer provides isolation, the second dielectric layer reduces point discharge, and the third dielectric layer provides additional protection. This segmentation allows the structure to address reliability issues while maintaining manageable complexity through functional division.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs composite materials by combining multiple dielectric layers with different properties. The first dielectric layer, second dielectric layer, and third dielectric layer are made of different materials that complement each other's characteristics. This composite approach enables the structure to simultaneously achieve good isolation performance, reduced point discharge, and improved reliability, resolving the contradiction between reliability enhancement and structural complexity.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS12237369B2Semiconductor device with shallow trench isolation having multi-stacked layers and method of forming the same

Publication Date: 2025.02.25 FUJIAN JINHUA INTEGRATED CIRCUIT CO LTD

AI summary

A semiconductor device includes a substrate; at least one trench located at a top surface of the substrate; and a first dielectric layer, a second dielectric layer and a third dielectric layer that are sequentially stacked on an inner wall of each of the at least one trench. A topmost surface of the first dielectric layer is lower than a topmost surface of the second dielectric layer and the top surface of the substrate, to form a first groove between the second dielectric layer and the substrate. An edge corner between the top surface of the substrate and the inner wall of each of the at least one trench is in a shape of a fillet curve. The fillet structure is smooth and round without a sharp corner, reducing point discharge and improving reliability of the shallow trench isolation structure.