Ultra-Deep Trench Isolation in IC Structures for Size Reduction

Solution Overview

Problem

Conventional integrated circuit (IC) structures face challenges in reducing feature size while maintaining electrical performance due to defects such as position misalignment and insufficient distance between components, which limits size reduction and increases manufacturing costs.

Innovation Solution

The implementation of an ultra-deep trench isolation structure that penetrates the substrate from the top surface to the bottom, structurally and physically isolating semiconductor devices within different regions, allowing for closer placement and reducing the overall size of the IC structure, and the use of vertical double-diffused metal oxide semiconductor (VDMOS) transistors for enhanced heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a sufficient distance is provided between low-side region and high-side region to sustain large voltage drop and maintain electrical characteristics, then electrical performance is maintained, but the size of the IC structure cannot be reduced

Engineering Contradiction:

Improveelectrical characteristicsVSAvoidIC structure size

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The substrate is divided into multiple isolated regions using ultra-deep trench isolation structures that extend through the entire substrate thickness. This segmentation allows adjacent regions to be placed closer together while maintaining electrical isolation, enabling size reduction without compromising electrical performance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The isolation approach transitions from planar (2D) separation to vertical (3D) separation by implementing trenches that extend through the entire substrate thickness. This dimensional change enables regions to be separated in the vertical dimension while maintaining close proximity in the horizontal plane, thus reducing overall IC size.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Productivity

If feature size is reduced to improve density and cost per unit, then manufacturing efficiency improves, but electrical performance deteriorates due to position misalignment and insufficient distance between components

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidelectrical performance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The substrate is divided into multiple isolated regions using ultra-deep trench isolation structures that extend through the entire substrate thickness. This segmentation allows adjacent regions to be placed closer together while maintaining electrical isolation, enabling size reduction without compromising electrical performance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The ultra-deep trench isolation structure acts as an intermediary barrier between adjacent semiconductor regions. This intermediary provides robust electrical isolation and prevents interference between regions, enabling closer placement of components while maintaining electrical performance even at reduced feature sizes.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If conventional isolation structures are used, then manufacturing is simpler, but isolation effectiveness is insufficient leading to position misalignment and electrical performance degradation

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidisolation effectiveness

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The isolation approach transitions from planar (2D) separation to vertical (3D) separation by implementing trenches that extend through the entire substrate thickness. This dimensional change enables regions to be separated in the vertical dimension while maintaining close proximity in the horizontal plane, thus reducing overall IC size.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The ultra-deep trench isolation structures are formed early in the manufacturing process, establishing robust isolation boundaries before subsequent device fabrication steps. This preliminary action ensures that position alignment and electrical isolation are predetermined and maintained throughout subsequent manufacturing steps.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11916075B2Integrated circuit structure with semiconductor devices and method of fabricating the same

Publication Date: 2024.02.27 UNITED MICROELECTRONICS CORP

AI summary

An integrated circuit (IC) structure includes a substrate having several regions, several semiconductor devices formed at the substrate and respectively within the regions, and an ultra-deep (UD) trench isolation structure formed in the substrate. The substrate has a top surface and a bottom surface oppositely, and the UD trench isolation structure formed in the substrate surrounds peripheries of each of the regions for structurally and physically isolating the semiconductor devices within different regions. The UD trench isolation structure penetrates the substrate by extending from the top surface of the substrate to the bottom surface of the substrate.