Capacitor Sidewall Support for Electrode Collapse

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Solution Overview

Problem

As semiconductor devices become more highly integrated, the challenge is to maintain a high capacitance in capacitors while preventing the lower electrode from collapsing due to its high aspect ratio, which can cause bending and adjacent electrodes to make contact.

Innovation Solution

The method involves forming a U-shaped capacitor electrode with an electrically insulating support that wraps around the electrode, using a first and second mold layer with different materials, and selectively etching to create a supporting layer pattern that reduces stress and prevents collapse.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the height of the lower electrode is increased to enlarge the contact area, then the capacitance is improved, but the lower electrode becomes susceptible to collapse due to high aspect ratio

Engineering Contradiction:

ImprovecapacitanceVSAvoidelectrode stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The lower electrode is divided into multiple segments along its height, with spacer layers positioned between segments. This segmentation reduces the aspect ratio of each individual electrode segment while maintaining the total height and capacitance of the capacitor structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Spacer layers are introduced as intermediary structures between the lower electrode segments. These spacers provide mechanical support and prevent collapse of the high-aspect-ratio electrode structure, enabling the electrode to maintain its shape while achieving the required capacitance.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the height of the lower electrode is increased to enlarge the contact area, then the capacitance is improved, but bending of the central or upper portion occurs causing adjacent electrodes to contact

Engineering Contradiction:

ImprovecapacitanceVSAvoidelectrode alignment

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The lower electrode is segmented into multiple sections with spacer layers in between. This segmentation provides structural reinforcement that prevents bending and maintains precise alignment of adjacent electrodes, avoiding unwanted contact while preserving the increased height needed for capacitance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Spacer layers are formed beforehand to provide preliminary structural support to the lower electrode during subsequent processing steps. This preliminary action prevents bending and maintains electrode alignment before the final capacitor structure is completed.

Inventive Principle:

Principle #10Preliminary action

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 allows for the formation of capacitors with high capacitance and reduced susceptibility to collapse, effectively addressing the issue of electrode stability and contact in densely integrated semiconductor devices.

Implementation Method 1

forming an electrically insulating support that directly contacts and wraps around at least a first portion of an outer surface of the first cylindrical capacitor electrode

Methodology Applied

Scientific EffectMechanical support:

Implementation Method 2

A capacitor dielectric layer is formed on an interior surface of the first cylindrical capacitor electrode

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 3

at least a portion of the first mold layer is selectively removed to expose at least a portion of the second mold layer

Methodology Applied

Scientific EffectSelective etching:

Data Source

PatentUS8119476B2Methods of forming integrated circuit capacitors having sidewall supports and capacitors formed thereby

Publication Date: 2012.02.21 SAMSUNG ELECTRONICS CO LTD

AI summary

In a method of forming a capacitor, a first mold layer pattern including a first insulating material may be formed on a substrate. The first mold layer pattern may have a trench. A supporting layer including a second insulating material may be formed in the trench. The second insulating material may have an etching selectivity with respect to the first insulating material. A second mold layer may be formed on the first mold layer pattern and the supporting layer pattern. A lower electrode may be formed through the second mold layer and the first mold layer pattern. The lower electrode may make contact with a sidewall of the supporting layer pattern. The first mold layer pattern and the second mold layer may be removed. A dielectric layer and an upper electrode may be formed on the lower electrode and the supporting layer pattern.