Capacitor Lower Electrode Contact Integrity via Seed Stopper

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Solution Overview

Problem

In highly integrated semiconductor devices, increasing the area of the lower electrode to achieve high capacitance is challenging due to partial removal of the plug during the seed removal process, leading to poor contact between the lower electrode and the plug.

Innovation Solution

A method involving the formation of a seed stopper and a sacrificial layer on an insulating interlayer with a plug, followed by forming an opening to expose the plug, depositing a seed on the inner wall, and then removing the sacrificial layer and seed to create a lower electrode with a concave hemi-spherical shape, ensuring good contact with the plug.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a hemi-spherical grain (HSG) is used as a seed for forming the lower electrode, then the area of the lower electrode can be increased to achieve high capacitance, but the plug may be partially removed during the seed removal process, leading to poor contact between the lower electrode and the plug

Engineering Contradiction:

Improvearea of lower electrodeVSAvoidcontact between lower electrode and plug

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The patent segments the seed structure into two distinct parts: a hemi-spherical grain (HSG) seed on the insulating interlayer and a separate plug structure. The HSG seed is formed first, then the plug is formed to contact the HSG seed. This segmentation allows the HSG to provide large surface area for capacitance while the plug maintains structural integrity and good electrical contact, as they are formed and removed in separate controlled steps.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies preliminary action by forming the HSG seed structure on the insulating interlayer before forming the plug. The HSG seed is prepared in advance with proper surface preparation and nucleation, ensuring that when the plug is subsequently formed, it will have excellent contact with the HSG seed. This preliminary preparation of the seed structure ensures reliable contact while maintaining the ability to achieve high capacitance through the HSG's large surface area.

Inventive Principle:

Principle #10Preliminary action

2Quantity of substance

If the area of the lower electrode is increased to obtain high capacitance, then capacitance is improved, but the plug may be partially removed during the seed removal process

Engineering Contradiction:

ImprovecapacitanceVSAvoidintegrity of plug

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent uses the HSG seed as an intermediary structure between the insulating interlayer and the plug. The HSG seed serves as a mediator that enables the formation of a large-area lower electrode through its hemi-spherical geometry, which provides high surface area to volume ratio. Meanwhile, the plug is formed as a separate entity that contacts the HSG seed, allowing the HSG to be removed after serving its purpose as a formation template, while the plug remains intact with good contact to the lower electrode.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies local quality by creating different structural characteristics in different regions: the HSG seed has a hemi-spherical shape optimized for surface area and capacitance, while the plug has a cylindrical shape optimized for structural integrity and electrical contact. The lower electrode is formed to conformally cover the HSG seed, creating a localized high-capacitance region, while the plug maintains its structural integrity through controlled formation and protection during the HSG removal process.

Inventive Principle:

Principle #3Local quality

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 enables a semiconductor device with a capacitor structure that maintains a stable and reliable contact between the lower electrode and the plug, enhancing capacitance and device reliability.

Implementation Method 1

the seed may be formed by a low pressure chemical vapor deposition (LPCVD) process or a rapid thermal chemical vapor deposition (RTCVD) process

Methodology Applied

Scientific EffectChemical Vapour Deposition: Chemical Vapour Deposition

Implementation Method 2

A lower electrode covering the seed may be formed on the inner wall of the opening

Methodology Applied

Scientific EffectPhysical Vapour Deposition: Physical Vapour Deposition

Data Source

PatentUS8039344B2Methods of forming a capacitor structure and methods of manufacturing a semiconductor device using the same

Publication Date: 2011.10.18 SAMSUNG ELECTRONICS CO LTD

AI summary

In a method of forming a capacitor, a seed stopper and a sacrificial layer is formed on an insulating interlayer having a plug therethrough. An opening is formed through the sacrificial layer and the seed stopper to expose the plug. A seed is formed on an innerwall of the opening. A lower electrode is formed covering the seed on the innerwall of the opening. The sacrificial layer and the seed are removed. A dielectric layer and an upper electrode are sequentially formed on the lower electrode.