Composite Bottom Electrode Capacitor for Oxidation-Stable Dielectric Formation

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Solution Overview

Problem

Existing back-end capacitor structures in semiconductor integrated circuits, such as MIM and MOM capacitors, face challenges in achieving high capacitance density, low leakage, and small voltage linearity.

Innovation Solution

A capacitor structure is proposed that includes a substrate with a bottom electrode composite layer comprising a first electrode layer and a second electrode layer, where the oxidation rate of the second electrode layer is lower than that of the first electrode layer. This structure also includes a dielectric structure layer and an optional top electrode layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single electrode layer is used in back-end capacitor structures, then the manufacturing process is simple, but the capacitance density and voltage linearity performance are insufficient

Engineering Contradiction:

Improveelectrode layer structureVSAvoidcapacitance density and voltage linearity

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The electrode layer is segmented into multiple sub-layers (first electrode layer and second electrode layer) with different materials and functions. The first electrode layer provides high conductivity while the second electrode layer provides oxidation resistance, allowing each layer to specialize in one function rather than requiring a single layer to perform all functions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The capacitor uses a composite electrode structure combining different materials (e.g., copper or aluminum in the first layer, and titanium nitride or tantalum nitride in the second layer) to achieve properties that neither material could provide alone - high conductivity from the first layer and oxidation resistance from the second layer.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If the bottom electrode layer is exposed to oxidation during dielectric layer formation, then the dielectric layer can be formed properly, but the capacitance stability deteriorates due to oxidation of the electrode

Engineering Contradiction:

Improvedielectric layer formationVSAvoidcapacitance stability

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The second electrode layer acts as an intermediary between the first electrode layer and the dielectric layer. It provides an oxidation-resistant barrier that protects the first electrode layer from oxidizing during dielectric layer formation, while still allowing the dielectric layer to be formed properly on top of it.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The oxidation-resistant second electrode layer is formed in advance before the dielectric layer formation process begins. This preliminary protective layer prevents oxidation from occurring during subsequent manufacturing steps, eliminating the need for complex in-situ protection measures.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If high conductivity materials are used for the bottom electrode, then the electrical performance is improved, but the oxidation resistance during dielectric formation deteriorates

Engineering Contradiction:

Improveelectrical conductivityVSAvoidoxidation during dielectric formation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The electrode is segmented into two functional layers: the first electrode layer uses high conductivity materials (copper, aluminum) optimized for electrical performance, while the second electrode layer uses oxidation-resistant materials (titanium nitride, tantalum nitride) optimized for chemical stability during manufacturing.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The composite electrode structure combines dissimilar materials with complementary properties - the first layer provides exceptional electrical conductivity while the second layer provides oxidation resistance, creating a multi-functional electrode system that neither material could achieve alone.

Inventive Principle:

Principle #40Composite materials

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 proposed capacitor structure minimizes the oxidation degree of the bottom electrode composite layer during the formation of the dielectric structure layer, thereby reducing the influence of oxidation on capacitance stability and improving the overall performance of the capacitor.

Implementation Method 1

an oxidation rate of a material of the second electrode layer is lower than an oxidation rate of a material of the first electrode layer. The capacitor structure also includes a dielectric structure layer on the bottom electrode composite layer.

Methodology Applied

Scientific EffectOxidation resistance: Oxidation

Data Source

PatentUS12205981B2Capacitor structure and forming method thereof

Publication Date: 2025.01.21 SEMICON MFG INT (SHANGHAI) CORP

AI summary

A capacitor structure and a forming method thereof are provided. The capacitor structure includes a substrate and a bottom electrode composite layer on the substrate. The bottom electrode composite layer includes a first electrode layer and a second electrode layer on the first electrode layer. An oxidation rate of a material of the second electrode layer is lower than an oxidation rate of a material of the first electrode layer. The capacitor structure also includes a dielectric structure layer on the bottom electrode composite layer.