Capacitor Liners Mitigate Capillary Forces in Etching

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Solution Overview

Problem

The fabrication of tall, thin capacitors in high-density integrated circuitry is challenging due to structural weakness and the risk of toppling or breaking, particularly when capacitor electrodes become tightly packed, leading to issues like short circuits caused by capillary forces during sacrificial material removal.

Innovation Solution

The use of liners along capacitor electrode surfaces to protect them during etching processes, which can be electrically conductive or insulative, and are incorporated into the capacitor structures to prevent short circuits and structural damage, employing techniques like vapor etching to mitigate capillary forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If capacitor electrodes are tightly packed to increase density, then device density is improved, but structural stability deteriorates causing toppling or breaking

Engineering Contradiction:

Improvedevice densityVSAvoidstructural stability

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The capacitor electrode structure is segmented into multiple components: a base electrode, a container-shaped storage node structure surrounding it, and a lattice structure providing additional support. This segmentation allows each component to fulfill specific structural functions, with the lattice providing distributed support points that prevent toppling while maintaining tight packing

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the capacitor structure are assigned different material properties and structural characteristics. The base electrode provides electrical function, the container-shaped storage node provides localized support and dielectric containment, and the lattice structure provides distributed mechanical support. This local differentiation optimizes both density and structural stability

Inventive Principle:

Principle #3Local quality

2Ease of manufacture

If wet etching is used to remove sacrificial material, then manufacturing simplicity is improved, but capillary forces cause adjacent storage nodes to be drawn together creating short circuits

Engineering Contradiction:

Improveetching process simplicityVSAvoidelectrical isolation between nodes

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

A liner material is introduced as an intermediary between the sacrificial material and the storage node structures. This liner serves multiple functions: it protects the storage nodes from direct contact with etchant during wet etching, prevents capillary forces from drawing nodes together, and can be selectively removed or retained based on process requirements

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The liner is deposited on the storage node structures before the sacrificial material removal process begins. This preliminary protective action ensures that when wet etching is subsequently performed, the storage nodes are already shielded from capillary forces and direct etchant exposure, preventing short circuit formation

Inventive Principle:

Principle #10Preliminary action

3Reliability

If liner material is deposited on capacitor electrode surfaces, then protection during etching is improved, but process complexity increases due to additional deposition and removal steps

Engineering Contradiction:

Improveelectrode protection during etchingVSAvoidfabrication process steps

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The liner material serves multiple functions simultaneously: it protects storage nodes during etching, prevents capillary force-induced short circuits, can serve as a barrier to etchant attack on underlying layers, and in some embodiments can be retained as part of the final capacitor structure. This multi-functionality justifies the additional process steps

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

This approach enhances the structural integrity and prevents short circuits in tightly packed capacitors, allowing for the successful formation of stable capacitor structures with improved reliability and density.

Implementation Method 1

employing techniques like vapor etching to mitigate capillary forces

Methodology Applied

Scientific EffectVapor etching:

Implementation Method 2

The use of liners along capacitor electrode surfaces to protect them during etching processes

Methodology Applied

Scientific EffectPhysical barrier protection:

Data Source

PatentUS9236427B2Multi-material structures and capacitor-containing semiconductor constructions

Publication Date: 2016.01.12 MICRON TECHNOLOGY INC

AI summary

Some embodiments include a method of forming a capacitor. An opening is formed through a silicon-containing mass to a base, and sidewalls of the opening are lined with protective material. A first capacitor electrode is formed within the opening and has sidewalls along the protective material. At least some of the silicon-containing mass is removed with an etch. The protective material protects the first capacitor electrode from being removed by the etch. A second capacitor electrode is formed along the sidewalls of the first capacitor electrode, and is spaced from the first capacitor electrode by capacitor dielectric. Some embodiments include multi-material structures having one or more of aluminum nitride, molybdenum nitride, niobium nitride, niobium oxide, silicon dioxide, tantalum nitride and tantalum oxide. Some embodiments include semiconductor constructions.