Through Via Capping Structure for High-Aspect-Ratio Memory Stacks

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Solution Overview

Problem

The challenge in semiconductor devices is forming through vias with high aspect ratios, which complicates electrical signal transfer between lower and upper wirings, leading to difficulties in data storage capacity enhancement.

Innovation Solution

A through via structure is developed, featuring a metal pattern with a barrier pattern on its sidewall and lower surface, and a capping pattern that contacts the upper surface of the via, ensuring the lowermost edge of the capping pattern is not higher than its central portion, thereby preventing outgassing of source gases and minimizing damage to neighboring structures during subsequent processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the number of stacks of memory cells is increased to enhance data storage capacity, then the data storage capacity is improved, but the aspect ratio of through via increases making formation difficult

Engineering Contradiction:

Improvedata storage capacityVSAvoidthrough via formation

Core Design Contradiction:

Quantity of substanceVSEase of manufacture

Solution Approach 1:

The through via structure is segmented into multiple functional layers: barrier pattern, metal pattern, and capping pattern. This segmentation allows each layer to be optimized independently for its specific function, making the overall high aspect ratio structure more manufacturable while maintaining high data storage capacity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The barrier pattern is formed on the sidewall and lower surface of the metal pattern before filling the through via. This preliminary action prevents outgassing of source gases during subsequent processes, protecting neighboring structures and enabling successful formation of high aspect ratio through vias

Inventive Principle:

Principle #10Preliminary action

2Ease of manufacture

If conventional through via structure is used, then manufacturing is simpler, but electrical characteristics are degraded due to damage from outgassing

Engineering Contradiction:

Improvethrough via formationVSAvoidelectrical characteristics

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The capping pattern is formed on the upper surface of the through via structure before subsequent processing steps. This preliminary capping action prevents outgassing of source gases from the through via during etching and other processes, protecting the electrical characteristics while maintaining manufacturability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The capping pattern acts as an intermediary protective layer between the through via structure and the etching environment. It mediates the harmful interaction between outgassing source gases and the metal pattern, preserving electrical characteristics during manufacturing

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11903199B2Through via structure, semiconductor device including the through via structure, and massive data storage system including the semiconductor device

Publication Date: 2024.02.13 SAMSUNG ELECTRONICS CO LTD

AI summary

A through via structure includes a through via and a capping pattern. The through via includes a metal pattern extending in a vertical direction, and a barrier pattern on a sidewall and a lower surface of the metal pattern. The capping pattern contacts an upper surface of the through via. A lowermost surface of an edge portion of the capping pattern is not higher than a lowermost surface of a central portion of the capping pattern.