Capacitor with Variable Sidewall Thickness for DRAM

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

High aspect ratio container-shaped storage nodes in capacitors are structurally weak and prone to toppling, twisting, and breaking, and existing methodologies fail to adequately address the need for increased capacitance in advanced DRAM technologies.

Innovation Solution

A capacitor structure with variable bottom cell plate (BCP) sidewall thickness and dual lattice structures is manufactured using a method involving a substrate with a multilayer stack, including isolation and lattice layers, recess formation, conformal storage layer deposition, photoresist processing, and selective etching to create container-shaped storage nodes with thinner upper and thicker lower sidewall segments, enhancing capacitance and aspect ratio while preventing toppling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If container-shaped storage nodes are formed with higher aspect ratios to achieve desired capacitance levels and decrease semiconductor real estate consumption, then capacitance increases and footprint decreases, but structural strength deteriorates causing toppling, twisting and breaking

Engineering Contradiction:

ImprovecapacitanceVSAvoidstructural strength

Core Design Contradiction:

Quantity of substanceVSStrength

Solution Approach 1:

The storage node is segmented into a base portion and an extended portion, with the base providing structural support and the extended portion providing capacitive surface area. This segmentation allows the node to achieve high aspect ratio while maintaining structural integrity through the reinforced base.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the storage node have different properties: the base portion has greater thickness and structural reinforcement, while the extended portion has optimized dimensions for capacitance. This local differentiation of properties allows simultaneous optimization of strength and capacitance.

Inventive Principle:

Principle #3Local quality

2Strength

If conventional lattice methodology is used to prevent toppling of high aspect ratio containers, then some structural support is provided, but it is insufficient to prevent toppling, twisting and breaking of increasingly high aspect ratio storage nodes

Engineering Contradiction:

Improvestructural supportVSAvoidresistance to toppling

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The base portion is formed with reinforced dimensions before the extended portion is created, establishing structural support in advance. The lattice structure is also formed preliminarily to provide additional support during subsequent processing steps.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The storage node combines different materials with complementary properties: the base portion uses materials optimized for structural strength, while the extended portion uses materials optimized for capacitance. The lattice structure provides additional composite reinforcement.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS9230966B2Capacitor and method of manufacturing the same

Publication Date: 2016.01.05 NAN YA TECH

AI summary

A capacitor includes a substrate, a multilayer over the substrate, a plurality of container-shaped storage node structures on the semiconductor substrate and surrounded by the multilayer, the storage node structure has a sidewall extending upwardly from the base to the top, where the sidewall includes an upper segment and a lower segment thinner than the upper segment, a capacitor dielectric material along a surface of each storage node structure, and a capacitor electrode material over the capacitor dielectric material.