Columnar Capacitor Array Fabrication to Prevent Top Support Layer Wear

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Solution Overview

Problem

The top support layer of columnar capacitors in DRAM fabrication is prone to wear, leading to insufficient support strength and tilting, which affects the performance and yield of the memory device.

Innovation Solution

A method is employed to adjust the thickness of the mask layer in the peripheral and array regions, using a photoresist layer to equalize thickness differences, and incorporate a third sacrificial layer and auxiliary layer to provide dual protection for the top support layer, preventing wear and ensuring stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a top support layer is provided to support the columnar capacitor, then the stability of the columnar capacitor is improved, but the top support layer is easily worn and support strength is insufficient

Engineering Contradiction:

Improvestability of columnar capacitorVSAvoidsupport strength of top support layer

Core Design Contradiction:

Stability of the object's compositionVSStrength

Solution Approach 1:

The patent applies preliminary action by forming a photoresist layer before removing the mask layer. This photoresist layer is deposited to fill capacitor holes and cover the mask layer, creating a protective barrier in advance. When the mask layer is subsequently removed, the photoresist layer prevents direct contact and wear on the top support layer, thereby maintaining its support strength while still providing the necessary stability for the columnar capacitor.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses the photoresist layer as an intermediary between the mask layer and the top support layer. This intermediary layer performs the function of protecting the top support layer from wear during the mask layer removal process. The photoresist layer absorbs the mechanical stress and wear that would otherwise directly affect the top support layer, allowing the support layer to maintain its integrity and support strength.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Strength

If the mask layer thickness is adjusted in array and peripheral regions, then the support strength is improved, but the manufacturing process complexity increases

Engineering Contradiction:

Improvesupport strength of top support layerVSAvoidfabrication process complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent applies local quality by forming the photoresist layer with different thicknesses in different regions. The photoresist layer is deposited to fill capacitor holes in the array region and cover the mask layer in both array and peripheral regions. This creates a locally optimized structure where the photoresist layer provides enhanced protection in regions where it is most needed, while maintaining appropriate thickness elsewhere. The selective thickness distribution addresses the support strength issue without requiring complete redesign of the entire fabrication 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

The method enhances the support strength of the top support layer, preventing tilting and improving the performance and yield of the columnar capacitors in DRAM fabrication.

Implementation Method 1

forming a photoresist material layer, where the photoresist material layer is filled in the plurality of capacitor holes and covers the mask layer in the array region and the mask layer in the peripheral region

Methodology Applied

Scientific EffectPhotoresist material deposition: Deposition (physical)

Implementation Method 2

etching back the photoresist material layer until the mask layer in the peripheral region is exposed, to form the photoresist layer

Methodology Applied

Scientific EffectEtching protection:

Implementation Method 3

removing the photoresist layer on a surface of the mask layer and etching the mask layer by using the top support layer as an etching stop layer

Methodology Applied

Scientific EffectEtching stop:

Data Source

PatentUS12406857B2Method for fabricating array structure of columnar capacitor and semiconductor structure

Publication Date: 2025.09.02 CHANGXIN MEMORY TECH INC

AI summary

Embodiments provide a method for fabricating an array structure of a columnar capacitor and a semiconductor structure. In the method, before a mask layer is removed, a photoresist layer is filled to adjust a thickness of the mask layer in a peripheral region and a thickness of the mask layer in an array region to be equal, thereby preventing a top support layer from being worn due to impacts of different thicknesses of the mask layers on a thickness of the top support layer. In addition, in the method, a third sacrificial layer and an auxiliary layer are further formed to perform dual protection on the top support layer, thereby preventing the top support layer from being thinned in subsequent processes, to increase support strength of the top support layer, thereby further preventing the columnar capacitor from tilting due to insufficient support strength of the top support layer.