Curved MIM Capacitor Electrode for Stable Breakdown Voltage

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional MIM capacitors are expensive to manufacture and suffer from low and uncontrolled breakdown voltage due to hillocks in the bottom electrode, particularly in aluminum-based designs.

Innovation Solution

A method to build MIM capacitors concurrently with interconnect structures without additional masks, involving etching a trench in a dielectric layer, depositing conformal metal, and using chemical mechanical polishing (CMP) to create a dish-shaped bottom electrode made of refractory metals, ensuring a smooth and hillock-free surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional MIM capacitors are built on aluminum interconnect with standard planar electrodes, then the manufacturing process is simpler, but the breakdown voltage is low and uncontrolled due to hillocks in the bottom electrode

Engineering Contradiction:

Improvebreakdown voltage consistencyVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies curvature by transforming the planar bottom electrode into a dish-shaped electrode with a concave surface. This curvature eliminates hillocks (protrusions) that cause uncontrolled breakdown voltage, creating a smooth, uniform electrode surface that improves breakdown voltage consistency and reliability

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent performs preliminary actions by etching trenches in the dielectric layer before depositing the bottom electrode metal. These trenches confine the metal deposition to specific regions, preventing hillock formation and ensuring a controlled, uniform electrode surface before subsequent processing steps

Inventive Principle:

Principle #10Preliminary action

2Manufacturing precision

If additional mask layers are used to create curved electrodes, then the electrode shape control improves, but the manufacturing cost increases

Engineering Contradiction:

Improveelectrode shape controlVSAvoidmanufacturing cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent replaces the mechanical/photochemical system of additional mask layers with a chemical-mechanical polishing (CMP) process. The CMP process uses chemical etching and mechanical polishing to create the dish-shaped electrode curvature, eliminating the need for extra mask fabrication and alignment steps while maintaining precise shape control

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical-chemical parameters of the electrode surface through CMP processing. By controlling polishing pressure, slurry composition, and processing time, the method transforms the electrode surface from planar to dish-shaped, achieving precise shape control through parameter optimization rather than additional lithography masks

Inventive Principle:

Principle #35Parameter changes

3Reliability

If multiple vias are used to reduce resistance, then the overall resistance decreases, but the device complexity and manufacturing difficulty increase

Engineering Contradiction:

Improveelectrical resistanceVSAvoidvia connection complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent transitions from reducing resistance through adding more via connections (increasing device complexity) to reducing resistance through expanding the electrode surface area in the lateral dimension. The dish-shaped electrode provides a larger effective contact area for via connections, reducing overall resistance without requiring additional vias or increasing via density

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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

This approach reduces manufacturing costs and enhances breakdown voltage consistency by eliminating hillocks, providing improved performance and reliability in MIM capacitors.

Implementation Method 1

a first chemical mechanical polishing (CMP) of the entire integrated circuit structure dishes and erodes bottom electrode metal adjacent the trench

Methodology Applied

Scientific EffectChemical mechanical polishing:

Implementation Method 2

depositing conformal metal in the via or contact hole, the tub, and the trench

Methodology Applied

Scientific EffectConformal deposition: Deposition (physical)

Data Source

PatentUS12588224B2Metal-insulator-metal (MIM) capacitors with curved electrode

Publication Date: 2026.03.24 MICROCHIP TECHNOLOGY INC

AI summary

A method for making a metal-insulator-metal (MIM) capacitors by etching a dielectric layer to form a via or contact hole, a tub, and a trench in the dielectric layer; depositing conformal metal in the via or contact hole, the tub, and the trench, wherein deposited conformal metal forms a via or contact in the via or contact hole; depositing a bottom electrode metal in the tub to form a bottom electrode of a metal-to-metal (MIM) capacitor; removing bottom electrode metal from the bottom electrode to form a dish-shape upper surface; depositing an insulator material on the bottom electrode to form an insulator layer of the MIM capacitor; and depositing a top electrode metal on the insulator layer to form a top electrode of the MIM capacitor.