Stacked Capacitor Structural Reinforcement via Segmented Electrode Deposition

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Solution Overview

Problem

Traditional methods for manufacturing DRAM capacitors face challenges in increasing capacitance while maintaining structural strength, as smaller capacitor dimensions lead to weakened structural integrity and potential twin bit failure during wet-etching.

Innovation Solution

A method for manufacturing high-strength structural stacked capacitors involves forming a laminate structure with a sacrificial layer, creating capacitor trenches, and selectively removing layers to form etching spaces, which allows for the deposition of upper electrode layers before and after wet etching, enhancing the structural strength and preventing electrode toppling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the height of the capacitor electrode is increased to increase capacitance, then the capacitance is improved, but the structural strength is weakened causing electrode toppling

Engineering Contradiction:

ImprovecapacitanceVSAvoidstructural strength

Core Design Contradiction:

Quantity of substanceVSStrength

Solution Approach 1:

The method forms a support structure and deposits part of the upper electrode layer on the first surface of the lower electrode before the wet etching process. This preliminary deposition strengthens the lower electrode structure in advance, preventing it from toppling during subsequent wet etching while allowing the electrode height to be increased for greater capacitance

Inventive Principle:

Principle #10Preliminary action

2Quantity of substance

If the thickness of the dielectric layer is decreased to increase capacitance, then the capacitance is improved, but the manufacturing precision becomes more difficult to control

Engineering Contradiction:

ImprovecapacitanceVSAvoiddielectric layer thickness control

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

Instead of solely relying on decreasing dielectric layer thickness to increase capacitance, the method increases the electrode contact surface area by forming electrodes on both the first and second surfaces of the lower electrode, and by increasing electrode height. This dimensional approach to increasing capacitance avoids the manufacturing precision challenges of ultra-thin dielectric layers

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Quantity of substance

If the electrode contact-surface area is increased to increase capacitance, then the capacitance is improved, but the device complexity increases

Engineering Contradiction:

ImprovecapacitanceVSAvoidelectrode structure complexity

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The upper electrode is segmented into multiple parts: a first upper electrode deposited before wet etching that covers the first surface of the lower electrode, and a second upper electrode deposited after wet etching that covers the second surface. This segmentation allows the electrode contact surface area to be increased while maintaining a manageable manufacturing process through sequential deposition steps

Inventive Principle:

Principle #1Segmentation

4Productivity

If the capacitor dimension is reduced to increase density, then the productivity is improved, but the structural strength is weakened

Engineering Contradiction:

Improvememory densityVSAvoidelectrode structural strength

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The support structure and first portion of the upper electrode are formed before the wet etching process, providing structural reinforcement to the lower electrode at reduced dimensions. This preliminary strengthening enables the production of high-density capacitors with reduced dimensions while preventing structural failure during manufacturing

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 method increases capacitance by enlarging the electrode contact-surface area and improves structural strength, preventing electrode toppling during wet etching, thereby enhancing the production yield and miniaturization of semiconductor memory devices.

Implementation Method 1

the first dielectric layer is deposited over the capacitor trenches to cover a first surface of each of the lower electrode layers

Methodology Applied

Scientific EffectPhysical Vapour Deposition: Physical Vapour Deposition

Implementation Method 2

the first upper electrode layer is deposited over the capacitor trenches to cover the surface of the first dielectric layers

Methodology Applied

Scientific EffectPhysical Vapour Deposition: Physical Vapour Deposition

Implementation Method 3

remove the sacrificial layer to form a plurality of etching spaces between the capacitor trenches via the openings to expose a second surface of each of the lower electrode layers

Methodology Applied

Scientific EffectWet Etching:

Data Source

PatentUS9349736B2Method for manufacturing high-strength structural stacked capacitor

Publication Date: 2016.05.24 MICRON TECHNOLOGY INC

AI summary

The instant disclosure relates to a method for manufacturing high-strength structural stacked capacitor. The novel feature of the instant disclosure is forming a part of upper electrode layer to cover the first/outer surface of each of the lower electrode layers before removing the sacrificial layer, and forming another part of upper electrode layer to cover the second/inner surface of each of the lower electrode layers after removing the sacrificial layer. Hence, the structure strength of the lower electrode layer in all process steps has been improved.