Semiconductor Memory Pillar Joint Conductor Bending

Solution Overview

Problem

In three-dimensionally stacked NAND-type flash memory, the joint portion between memory pillars can exhibit different electrical characteristics than the rest of the pillar, leading to reduced coupling capacities and potentially deteriorated erasure characteristics, affecting data reliability.

Innovation Solution

The semiconductor memory design includes a memory pillar structure with a joint portion between columnar sections, where the conductor adjacent to the joint portion has a bending portion that enhances coupling capacities, ensuring consistent voltage application across the pillar.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a joint portion is formed between columnar sections of memory pillars to enable three-dimensional stacking, then device complexity and manufacturing flexibility are improved, but electrical characteristics deteriorate due to reduced coupling capacities

Engineering Contradiction:

Improvepillar structure flexibilityVSAvoiderasure characteristics

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The conductor is designed with a bending portion that follows the curved shape of the joint portion between columnar sections. This curvature allows the conductor to maintain close proximity to the entire pillar surface, ensuring consistent electrical coupling and voltage application across the joint region, thereby preventing deterioration of erasure characteristics while accommodating the segmented pillar structure.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The conductor configuration is locally adapted to match the specific geometry of the joint portion. By bending the conductor to follow the joint's curvature, the design creates a localized optimization of electrical coupling at the critical joint region without affecting the overall pillar structure, thus maintaining reliable erasure characteristics throughout the memory device.

Inventive Principle:

Principle #3Local quality

2Reliability

If conductors are positioned to follow the joint portion curvature, then coupling capacity is improved, but device complexity increases

Engineering Contradiction:

Improvecoupling capacityVSAvoidconductor configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The conductor is designed with a bending portion that follows the curved shape of the joint portion between columnar sections. This curvature allows the conductor to maintain close proximity to the entire pillar surface, ensuring consistent electrical coupling and voltage application across the joint region, thereby preventing deterioration of erasure characteristics while accommodating the segmented pillar structure.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentUS10957710B2Three dimensional semiconductor memory including pillars having joint portions between columnar sections

Publication Date: 2021.03.23 KIOXIA CORP

AI summary

According to one embodiment, a semiconductor memory includes a plurality of conductors stacked with insulators being interposed therebetween and a pillar through the plurality of conductors. The pillar includes a first columnar section, a second columnar section, and a joint portion between the first columnar section and the second columnar section. The pillar comprises portions that cross the respective conductors and that each function as part of a transistor. The plurality of conductors include a first conductor. The first conductor is closest to the joint portion among the plurality of conductors through the second columnar section, and includes a bending portion formed along the joint portion.