Columnar Capacitor Array Support Structure to Prevent Tilt

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Solution Overview

Problem

Existing methods for fabricating columnar capacitors in DRAM devices face issues with the top support layer being easily worn, leading to insufficient support strength and potential tilting or peeling of the capacitor, which affects performance.

Innovation Solution

A method involving the stacking of multiple layers on a substrate, including a mask layer, initial and supplementary support layers, sacrificial layers, and conductive pads, where the thickness of the mask layer in the peripheral region is adjusted to match that in the array region, and a supplementary support layer is formed to enhance the top support layer's strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single top support layer is used to support the columnar capacitor, then the structure is simple, but the support strength is insufficient and the top support layer is easily worn

Engineering Contradiction:

Improvesupport layer structureVSAvoidsupport strength

Core Design Contradiction:

Device complexityVSStrength

Solution Approach 1:

The top support layer is divided into two separate layers: an initial support layer and a supplementary support layer. This segmentation allows each layer to perform specific functions - the initial support layer provides base support during fabrication, while the supplementary support layer enhances mechanical strength and prevents wear during subsequent processing steps.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The initial support layer is formed beforehand to provide preliminary support during the capacitor formation process. This preliminary action ensures that the columnar capacitor structure is properly supported before the supplementary support layer is added to enhance protection against wear and mechanical damage.

Inventive Principle:

Principle #10Preliminary action

2Ease of manufacture

If the mask layer thickness is uniform across the substrate, then the manufacturing process is simple, but the top support layer becomes exposed and worn in the peripheral region

Engineering Contradiction:

Improvemask layer fabricationVSAvoidtop support layer integrity

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The mask layer is designed with different thicknesses in different regions: a first thickness in the array region and a second (greater) thickness in the peripheral region. This local quality variation ensures that when portions of the mask layer are removed, the top support layer remains protected in the peripheral region while allowing proper exposure and support in the array region.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS12342554B2Method for fabricating array structure of columnar capacitor and semiconductor structure

Publication Date: 2025.06.24 CHANGXIN MEMORY TECH INC

AI summary

Embodiments provide a method for fabricating an array structure of a columnar capacitor and a semiconductor structure, relating to the field of semiconductor manufacturing technology. In the method, before a mask layer is removed, a thickness of the mask layer in the peripheral region is first adjusted to be equal to a thickness of the mask layer in the array region, thereby avoiding damage to a top support layer caused by different thicknesses of the mask layer. Moreover, in the method, a thickness of the top support layer is increased by means of a supplementary support layer, to increase support strength of the top support layer, thereby further preventing occurrence of tilt of the columnar capacitor due to insufficient support strength of the top support layer.