Capacitor Lower Electrode Tilting Prevention via Bridge Insulating Layer

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Solution Overview

Problem

In highly integrated semiconductor devices, conventional methods for manufacturing cylindrical cell capacitors face challenges such as tilting and electrical shorts due to insufficient etch selectivity and inclined profiles of the lower electrodes, leading to bridging issues during the rinsing and drying processes.

Innovation Solution

A method involving the formation of a mesh-type bridge insulating layer with an etch selectivity of 500 or greater between the mold oxide layer and the bridge insulating layer, using anhydrous HF gas and IPA, to prevent tilting and electrical shorts by maintaining a controlled etching process and ensuring adequate gap formation between electrodes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the thickness of the mold oxide layer is increased to obtain high capacitance, then the capacitance of the capacitor is improved, but the etch selectivity between the mold oxide layer and photoresist pattern becomes insufficient and the sidewalls of the electrode region become inclined

Engineering Contradiction:

ImprovecapacitanceVSAvoidetch selectivity and sidewall profile

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

A bridge insulating layer is introduced as an intermediary structure between adjacent electrode regions. This layer extends from the top surface of the mold oxide layer down to a first depth, providing structural support that prevents tilting of lower electrodes and maintains proper gap spacing, thereby resolving the manufacturing precision issues that arise when using thick mold oxide layers for high capacitance

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The bridge insulating layer is formed with a mesh-type pattern that segments the space between adjacent electrodes. This segmentation approach provides localized support at critical points while maintaining adequate gaps between electrodes, allowing the mold oxide layer to be sufficiently thick for high capacitance without causing tilting or electrical shorts

Inventive Principle:

Principle #1Segmentation

2Ease of manufacture

If conventional wet etching is used to remove the mold oxide layer, then the process is simple and cost-effective, but the lower electrode becomes tilted or bridged during the rinsing and drying processes

Engineering Contradiction:

Improveetching process simplicityVSAvoidlower electrode alignment

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The bridge insulating layer is formed beforehand to provide structural cushioning and support during the wet etching, rinsing, and drying processes. This pre-formed structure prevents the lower electrode from tilting or bridging by maintaining the integrity of the gap between adjacent electrodes throughout the subsequent processing steps

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The bridge insulating layer acts as an intermediary structural element that remains in place during wet etching and subsequent rinsing/drying processes. It provides mechanical support that prevents direct contact between adjacent lower electrodes, thereby preventing tilting and bridging while allowing the use of simple conventional wet etching methods

Inventive Principle:

Principle #24Intermediary (Mediator)

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 method effectively prevents tilting and electrical shorts by maintaining a controlled etching process and ensuring adequate gap formation between electrodes, enhancing the manufacturing process for semiconductor capacitors with improved etch selectivity and reduced over-etching risks.

Implementation Method 1

removing the mold oxide layer using an etching gas with an etch selectivity of 500 or greater for the mold oxide layer with respect to the bridge insulating layer

Methodology Applied

Scientific EffectEtch selectivity:

Implementation Method 2

using anhydrous HF gas and IPA, to prevent tilting and electrical shorts by maintaining a controlled etching process

Methodology Applied

Scientific EffectChemical etching: Chemical Bonding

Data Source

PatentUS7435644B2Method of manufacturing capacitor of semiconductor device

Publication Date: 2008.10.14 SAMSUNG ELECTRONICS CO LTD

AI summary

Provided is a method of manufacturing a capacitor of a semiconductor device, which can prevent tilting or an electrical short of a lower electrode. In the method, a mesh-type bridge insulating layer is formed above the contact plug on a mold oxide layer. The mold oxide layer and the bridge insulating layer are etched to define an electrode region. The mold oxide layer is removed using an etching gas having an etch selectivity of 500 or greater for the mold oxide layer with respect to the bridge insulating layer.