Semiconductor Memory Stack Slits for Stable End-Cell Characteristics

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Solution Overview

Problem

Existing semiconductor memory devices face challenges in maintaining consistent performance due to characteristic fluctuations at the end portions of stacked bodies, which can be attributed to the presence of dummy regions that do not contribute to the device's functionality.

Innovation Solution

The implementation of a structure with slits and pillars in the stacked body, where the upper end portions of certain slits are fully or partially covered by strips of material, and the inclusion of dummy pillars in end portions to maintain periodicity and accuracy, reducing the area of non-functional dummy regions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If dummy regions are provided at end portions of stacked body to prevent characteristic fluctuation, then reliability of memory cells is improved, but area occupied by non-functional regions increases

Engineering Contradiction:

Improvecharacteristic stability of memory cellsVSAvoidarea of dummy region

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The stacked body is divided into multiple segments by introducing slits that extend in the stacking direction. These slits partition the structure into distinct regions, allowing the end portions to be treated differently while maintaining overall functionality. The segmentation enables reduced dummy regions by creating independent structural units that can stabilize characteristics locally without requiring extensive dummy areas.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different structural configurations are applied to different regions of the stacked body. Specifically, the end portions are equipped with slits and covering structures that provide local stabilization, while the central regions maintain their original configuration. This local quality approach allows characteristic stability to be achieved precisely where needed (at end portions) without extending dummy regions throughout the entire structure.

Inventive Principle:

Principle #3Local quality

2Area of stationary object

If slits are introduced in stacked body to reduce dummy region area, then area efficiency is improved, but manufacturing precision requirements increase

Engineering Contradiction:

Improvearea of dummy regionVSAvoidprecision of pillar formation

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

Upper end portions of the slits are covered with conductive or insulating materials before the pillar formation process. This preliminary covering action establishes precise reference boundaries that guide subsequent pillar formation, ensuring that pillars are formed with accurate positioning and dimensions. The pre-established covering structures serve as templates that reduce the precision burden on later manufacturing steps.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The covering materials (conductive or insulating layers) introduced at the slit openings act as intermediary structures that mediate between the slit geometry and the pillar formation process. These intermediary layers provide well-defined interfaces and boundaries that facilitate precise pillar formation, effectively translating the complex slit structure into manageable formation zones for the pillars.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Stability of the object's composition

If strips of material cover upper end portions of slits, then structural stability is improved, but device complexity increases

Engineering Contradiction:

Improvestructural stability of stacked bodyVSAvoidcomplexity of slit covering structure

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The covering structures at the slit openings serve multiple functions simultaneously: they provide structural stability to the stacked body, define boundaries for pillar formation, and can serve as electrical connections or isolation elements depending on whether conductive or insulating materials are used. This multi-functionality reduces the need for separate dedicated structures, thereby limiting the increase in device complexity despite the added stability features.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS20260073954A1Semiconductor memory device and method for manufacturing semiconductor memory device

Publication Date: 2026.03.12 KIOXIA CORP

AI summary

A semiconductor memory device includes a stacked body including a plurality of first layers and a plurality of second layers alternately stacked one by one, a plurality of slits extending in the stacked body in a stacking direction of the stacked body and in a first direction intersecting the stacking direction, the slits dividing the stacked body in a second direction intersecting the first direction and the stacking direction, and a plurality of pillars disposed between the plurality of slits and extending in the stacked body in the stacking direction.