Semiconductor Isolation Block via Staggered Trench Oxidation

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Solution Overview

Problem

Existing semiconductor integrated circuits face challenges in efficiently utilizing space for high-voltage elements while minimizing cost and preventing wafer warpage due to uneven stress distribution.

Innovation Solution

Forming a high-voltage isolation block by etching parallel trenches and staggered strip structures in the semiconductor substrate, followed by thermal oxidation to connect oxidized portions and distribute stress evenly, allowing for flexible circuit arrangement and reduced processing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high-voltage elements are separated by a certain distance with isolation blocks, then electrical signals can be transmitted without being affected by high voltages, but the overall size of the component increases and space utilization decreases

Engineering Contradiction:

Improveelectrical signal transmissionVSAvoidspace utilization

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The isolation block is segmented into multiple oxidized portions that are connected together, forming a distributed isolation structure. This segmentation allows the isolation function to be achieved through multiple smaller units rather than a single large block, improving space utilization while maintaining electrical isolation reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The oxidized portions are nested within trenches that are formed in the semiconductor substrate. The isolation block structure is embedded within the substrate architecture, with oxidized portions positioned within defined trench regions, allowing efficient space utilization while providing effective electrical isolation.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Ease of manufacture

If conventional isolation block formation methods are used, then manufacturing process is simpler, but wafer warpage occurs due to uneven stress distribution

Engineering Contradiction:

Improvemanufacturing process simplicityVSAvoidwafer warpage

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The isolation block employs oxidized portions with different local properties - some portions are fully oxidized while others remain as original semiconductor material. This local quality variation allows stress distribution to be optimized at different locations within the isolation block, preventing wafer warpage while maintaining manufacturing feasibility.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The isolation block is formed as a composite structure combining oxidized semiconductor material with remaining unoxidized semiconductor material. This composite structure provides both the electrical isolation function and the mechanical stress distribution needed to prevent wafer warpage, while being formed through standard thermal oxidation processes.

Inventive Principle:

Principle #40Composite materials

3Adaptability or versatility

If more isolation blocks are formed to cover wider areas, then high-voltage element arrangement flexibility increases, but processing cost increases

Engineering Contradiction:

Improvecircuit arrangement flexibilityVSAvoidprocessing cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The thermal oxidation process used to form the isolation block serves multiple functions simultaneously: it creates the electrical isolation structure, provides stress distribution to prevent warpage, and can be applied across wide substrate areas. This multi-functionality allows the same process to be used regardless of the isolation block size or configuration needed, maintaining cost-effectiveness while providing circuit arrangement flexibility.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 effectively prevents wafer warpage and enhances the flexibility of high-voltage circuit arrangements, reducing processing costs and enabling efficient transmission of electrical signals under high voltages.

Implementation Method 1

performing a thermal oxidation process, such that the strip structures are oxidized to form a plurality of oxidized portions

Methodology Applied

Scientific EffectThermal oxidation: Oxidation

Data Source

PatentUS10115626B1Methods for forming isolation blocks of semiconductor devices, semiconductor devices and methods for manufacturing the same

Publication Date: 2018.10.30 VANGUARD INTERNATIONAL SEMICONDUCTOR CORPORATION

AI summary

A method for forming an isolation block of a semiconductor device includes providing a semiconductor substrate, performing an etching process to form a plurality of trenches which are parallel to each other in the semiconductor substrate, wherein a plurality of strip structures are between the trenches. The strip structures and the trenches occupy a first region in the semiconductor substrate, and the strip structures are arranged staggered with the trenches. The method further includes performing a thermal oxidation process, such that the strip structures are oxidized to form a plurality of oxidized portions, wherein the oxidized portions extended into the trenches and connected to each other to form an isolation block in the semiconductor substrate.