Memory Die Lateral Etch Stops for Access Line Isolation Control

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Solution Overview

Problem

In memory die manufacturing, the variability in removing sacrificial material between dielectric layers can lead to conductor materials interfering with electrically isolated regions, resulting in inefficient use of space and the need for non-functional regions to prevent interference, which reduces the compactness and efficiency of memory die configurations.

Innovation Solution

Incorporating lateral etch stops, such as trenches with deposited materials, to limit the extent of void formation during sacrificial material removal, allowing for more precise control of conductor material placement and exclusion from intended isolation regions, thereby optimizing the memory die's area utilization without increasing the number of formation operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If sacrificial material is removed to form conductive access lines, then conductor placement is enabled, but the removal extent is variable or indeterminate causing non-functional regions

Engineering Contradiction:

Improveconductor access line formationVSAvoidsacrificial material removal extent

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent introduces an intermediary material layer between the sacrificial material and the etch process. This intermediary layer acts as a controlled barrier that regulates the etch front propagation, ensuring precise termination of sacrificial material removal. The intermediary layer is selectively removed after enabling controlled void formation, thus mediating between the need for complete sacrificial material removal and the need for precise boundary control.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies preliminary action by forming a protective or sacrificial intermediary layer before the main etching process. This layer is pre-positioned to define the exact boundary where etching should stop. The intermediary layer is designed to be removed selectively after it has served its boundary-defining purpose, allowing precise control over the void formation extent before conductor material deposition.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If non-functional regions are created to prevent unintended conductor formation, then conductor interference is avoided, but memory die area utilization decreases

Engineering Contradiction:

Improveconductor formation controlVSAvoidmemory die area utilization

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent extracts the boundary control function from the traditional non-functional region approach. Instead of leaving large non-functional areas to prevent unintended conductor formation, the invention extracts and isolates the sacrificial material removal process to only the necessary regions using the intermediary layer as a precise boundary marker. This allows functional areas to be maximized while maintaining reliable conductor formation control.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/layout-based solution (creating non-functional regions to prevent conductor interference) with a process-based solution (using an intermediary material layer to control etch termination). This substitution eliminates the need for conservative spacing and non-functional regions, allowing tighter packing of functional elements while maintaining conductor formation reliability through chemical/process control.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enables a more compact configuration of features by preventing conductor material intrusion into isolated regions, improving the memory die's area utilization and operational efficiency while maintaining the integrity of electrical isolation.

Implementation Method 1

Incorporating lateral etch stops, such as trenches with deposited materials, to limit the extent of void formation during sacrificial material removal

Methodology Applied

Scientific EffectEtch stop:

Implementation Method 2

limit the extent of void formation during sacrificial material removal, allowing for more precise control of conductor material placement and exclusion from intended isolation regions

Methodology Applied

Scientific EffectPhysical barrier: Physical Containment

Data Source

PatentUS20240040787A1Lateral etch stops for access line formation in a memory die

Publication Date: 2024.02.01 MICRON TECHNOLOGY INC

AI summary

Methods, systems, and devices for lateral etch stops for access line formation in a memory die are described. A memory die may be formed with isolation regions that provide an etch stop to limit the extent of voids formed by removing a sacrificial material between layers of a dielectric region. For example, first trenches may be formed through a stack of alternating layers of a dielectric material and a sacrificial material, in which one or more materials may formed. Second trenches may be formed between a first trench and an array portion of the memory die, or between pairs of the first trenches, which may support the removal of at least a portion of the sacrificial material to form voids for access line formation. However, the materials formed in the first trenches may provide a boundary, or a restriction zone, that limits an extent of the material removal operation.