Trench Isolation Structure With Polycrystalline-Amorphous Filling

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Solution Overview

Problem

Existing trench isolation structures face challenges such as inadequate filling of trenches and defects that affect subsequent processing, particularly in high aspect ratio trenches, leading to electrical isolation issues in semiconductor devices.

Innovation Solution

A trench isolation structure is formed with a polycrystalline material partially filled in the trench, followed by an amorphous layer over the polycrystalline material, using deposition and ion implantation processes to ensure complete filling and electrical isolation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If trenches are made deeper to improve electrical isolation, then isolation effectiveness is improved, but filling completeness deteriorates

Engineering Contradiction:

Improveelectrical isolation effectivenessVSAvoidtrench filling completeness

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The trench filling process is segmented into multiple deposition steps with alternating polycrystalline and amorphous layers. This segmentation allows each layer to be optimized for its specific function - polycrystalline layers provide structural integrity while amorphous layers ensure complete gap filling, collectively solving the contradiction between deep trench isolation and complete filling.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses composite material structure with alternating polycrystalline and amorphous silicon layers. The polycrystalline silicon provides mechanical strength and electrical isolation, while the amorphous silicon fills gaps effectively. This composite approach resolves the contradiction by combining materials with complementary properties to achieve both deep trench isolation and complete filling.

Inventive Principle:

Principle #40Composite materials

2Device complexity

If single material is used to simplify structure, then device complexity is reduced, but isolation effectiveness deteriorates

Engineering Contradiction:

Improvestructure complexityVSAvoidelectrical isolation effectiveness

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent applies local quality by using different material properties in different regions of the trench structure. Polycrystalline silicon is used in regions requiring structural integrity and electrical isolation, while amorphous silicon is used in regions requiring complete gap filling and defect reduction. This localized material differentiation improves isolation effectiveness without significantly increasing overall device complexity.

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 solution provides effective electrical isolation by ensuring complete trench filling and reduces defects, enhancing the reliability and performance of semiconductor devices.

Implementation Method 1

depositing a polycrystalline material at least partially in the trench and forming an amorphous layer over the polycrystalline material

Methodology Applied

Scientific EffectDeposition: Deposition (physical)

Implementation Method 2

using deposition and ion implantation processes to ensure complete filling and electrical isolation

Methodology Applied

Scientific EffectIon implantation: Ion Implantation

Data Source

PatentUS12519008B2Trench isolation structures and methods of making thereof

Publication Date: 2026.01.06 GLOBALFOUNDRIES SINGAPORE PTE LTD

AI summary

A trench isolation structure and method of making the same is provided. The trench isolation structure comprises a trench in a substrate, the trench having a bottom surface and sidewalls. A polycrystalline material is at least partially in the trench and an amorphous layer is over the polycrystalline material.