High-Voltage Transistor Isolation Structure for Breakdown Voltage

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Solution Overview

Problem

Existing manufacturing processes for high-voltage transistors fail to enhance breakdown voltage while maintaining compatibility with medium- and low-voltage transistors, leading to isolation regions designed for high voltage failing to meet design requirements.

Innovation Solution

A method is proposed where isolation regions for high-voltage transistors are formed with different structures and methods than those for medium- and low-voltage transistors, enhancing voltage-withstanding capability while maintaining manufacturing compatibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If isolation regions for high-voltage transistors are formed using the same process as medium- and low-voltage transistors, then manufacturing compatibility is maintained, but breakdown voltage requirements are not met

Engineering Contradiction:

Improvebreakdown voltageVSAvoidmanufacturing compatibility

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent segments the manufacturing process into distinct stages: forming isolation regions for medium- and low-voltage transistors first, then forming separate isolation regions for high-voltage transistors with different parameters. This allows each transistor type to have optimized isolation characteristics while using a unified manufacturing platform.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by forming isolation regions with different depths and doping concentrations in different locations on the substrate. High-voltage transistor isolation regions are formed deeper with higher doping concentrations to withstand higher voltages, while medium- and low-voltage regions use shallower, less heavily doped isolation regions.

Inventive Principle:

Principle #3Local quality

2Reliability

If isolation regions are formed deeper in the substrate, then voltage-withstanding capability is enhanced, but manufacturing complexity increases

Engineering Contradiction:

Improvevoltage-withstanding capabilityVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses preliminary action by forming the isolation regions for medium- and low-voltage transistors before forming the isolation regions for high-voltage transistors. This sequential approach allows the manufacturing process to build upon previous steps rather than requiring completely separate processes.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies parameter changes by modifying the depth and doping concentration parameters of isolation regions based on the specific voltage requirements of different transistor types. The isolation region depth is increased and doping concentration is heightened for high-voltage applications while maintaining standard parameters for lower voltage devices.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20250267933A1Method of forming high voltage transistor and structure resulting therefrom

Publication Date: 2025.08.21 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A semiconductor structure includes a first zone and a second zone. The first zone includes: a first transistor on a substrate; and a first isolation region in the substrate and defining a boundary of the first transistor. The second zone includes a second transistor on the substrate, wherein the second transistor includes: a second isolation region in the substrate and a gate electrode disposed over the substrate, the gate electrode partially overlapping the second isolation region; and a barrier layer below and spaced apart from the second isolation region.