MIM Capacitor Corner Layout for BEOL Stress Reduction

Solution Overview

Problem

Stress concentrations and accumulations at right-angle corners of Metal-Insulator-Metal (MIM) capacitor conductor plate layers lead to cracks and delamination, increasing defect density in semiconductor integrated circuits.

Innovation Solution

A method to modify the mask design by eliminating right-angle corners and transforming them into obtuse-angle corners in the conductor plate layers of MIM structures, reducing stress concentration and defect density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If right-angle corners are used in conductor plate layers, then manufacturing is simpler, but stress concentrations occur leading to cracks and delamination

Engineering Contradiction:

Improveease of manufactureVSAvoidreliability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies curvature by replacing right-angle corners with rounded corners in conductor plate layers. This geometric modification eliminates stress concentration points that occur at sharp corners, thereby preventing cracks and delamination while maintaining manufacturing simplicity through standard photolithography processes.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent changes the geometric parameter of corner angles from 90 degrees to obtuse angles (greater than 90 degrees). This parameter modification redistributes stress more evenly across the conductor plate structure, reducing stress accumulation and improving reliability without significantly complicating the manufacturing process.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If right-angle corners are used in conductor plate layers, then design is simpler, but stress accumulations result in defects

Engineering Contradiction:

Improvedevice complexityVSAvoidstress accumulation

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent applies curvature by replacing right-angle corners with rounded corners in conductor plate layers. This geometric modification eliminates stress concentration points that occur at sharp corners, thereby preventing cracks and delamination while maintaining manufacturing simplicity through standard photolithography processes.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent converts the potentially harmful stress concentration at corners into a beneficial distributed stress pattern by using rounded corners. The curvature transforms the stress flow, turning what would be concentration points into areas of stress distribution, thereby eliminating defects while adding minimal complexity to the design.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If right-angle corners are eliminated and transformed into obtuse-angle corners, then stress accumulation is reduced, but manufacturing complexity increases

Engineering Contradiction:

ImprovereliabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies curvature by replacing right-angle corners with rounded corners in conductor plate layers. This geometric modification eliminates stress concentration points that occur at sharp corners, thereby preventing cracks and delamination while maintaining manufacturing simplicity through standard photolithography processes.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent changes the geometric parameter of corner angles from 90 degrees to obtuse angles (greater than 90 degrees). This parameter modification redistributes stress more evenly across the conductor plate structure, reducing stress accumulation and improving reliability without significantly complicating the manufacturing process.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12557655B2Passive device structure stress reduction

Publication Date: 2026.02.17 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

Methods for forming a back-end-of-line (BEOL) passive device structure are provided. A method according to the present disclosure includes depositing a first conductor layer over a substrate, patterning the first conductor layer to form a patterned first conductor layer, depositing a first insulation layer over the patterned first conductor layer, depositing a second conductor layer over the first insulation layer, patterning the second conductor layer to form a patterned second conductor layer, depositing a second insulation layer over the patterned second conductor layer, depositing a third conductor layer over the second insulation layer, and patterning the third conductor layer to form a patterned third conductor layer. The patterning of the first conductor layer includes removing a right-angle edge of the first conductor layer.