DRAM Capacitor Contact Structure With Electrode Cover Layer Support

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Solution Overview

Problem

The fabrication of dynamic random access memory (DRAM) capacitors faces issues with contact resistance due to voids or loading effects during the chemical polishing process, which are caused by through-holes that are either too small or too large, affecting the contact structure's integrity.

Innovation Solution

A semiconductor structure with a contact structure comprising a first and second contact layer, where the first contact layer has a greater width than the second, and the resistivity of the conductive structure is not greater than that of the electrode cover layer, increasing the contact area and reducing resistance while supporting the structure during polishing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the through-hole is made larger to reduce contact resistance, then the contact resistance decreases, but loading effect or contact structure depression occurs during chemical polishing

Engineering Contradiction:

Improvecontact resistanceVSAvoidcontact structure integrity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The contact structure is divided into multiple segments: the through-hole, the contact structure itself, and the electrode cover layer. By segmenting the contact structure into these distinct parts, the patent allows the through-hole to be larger for better electrical contact while the contact structure and electrode cover layer provide mechanical support to prevent depression during polishing.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The electrode cover layer is designed to extend over the through-hole and contact structure, creating a protective cushion before the chemical polishing process. This pre-positioned cover layer prevents the contact structure from deforming or depressing during polishing, even when the through-hole is large.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Manufacturing precision

If the through-hole is made smaller to maintain contact structure integrity, then loading effect and depression are avoided, but voids appear in the contact structure causing increased contact resistance

Engineering Contradiction:

Improvecontact structure integrityVSAvoidcontact resistance

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The contact structure is segmented into the through-hole region and the contact structure region, with the electrode cover layer providing additional segmentation. This allows the through-hole to be optimized for electrical contact while the contact structure maintains integrity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The electrode cover layer is positioned beforehand to cover and protect the contact structure. This protective layer prevents void formation and maintains contact structure integrity even when the through-hole is sized optimally for electrical contact.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If the through-hole penetrates deep into the electrode cover layer to reduce contact resistance, then the contact resistance decreases, but the structural support is reduced

Engineering Contradiction:

Improvecontact resistanceVSAvoidstructural support

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The structure is segmented into distinct functional zones: the through-hole for electrical contact, the contact structure for mechanical and electrical function, and the electrode cover layer for protection. This segmentation allows each part to be optimized independently.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The electrode cover layer is positioned in advance to provide structural support over the through-hole. This allows the through-hole to penetrate deeply for low contact resistance while the cover layer maintains structural integrity and provides cushioning during subsequent processing.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentUS12519014B2Semiconductor structure including an electrode cover layer over a capacitor of a dynamic random access memory (DRAM) formed in a substrate, and a contact structure electrically connected to the electrode cover layer, and method of making the same

Publication Date: 2026.01.06 CHANGXIN MEMORY TECH INC

AI summary

A semiconductor structure includes: an electrode cover layer; a first conductive structure on the electrode cover layer; a contact structure, including a first and a first contact layer. The first contact layer is in contact with the first conductive structure, the bottom of the second contact layer is in contact with the top of the first contact layer, the width of the first contact layer is greater than the width of the bottom of the second contact layer, the lower surface of the contact structure is not lower than the lower surface of the electrode cover layer, and the resistivity of the first conductive structure is not greater than that of the contact structure and is not greater than that of the electrode cover layer.