Memory Device Reticle Adjustment for Block Bending Errors

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Solution Overview

Problem

Conventional memory device fabrication processes often result in block bending errors due to stress and process variations, leading to deviations in the intended locations of memory cell pillars and conductive structures, which can cause damage or operational issues if left untreated.

Innovation Solution

Reticle adjustments are performed during the fabrication of memory devices to compensate for potential pillar and block bending errors, ensuring that sub-block dividers and conductive structures are formed at corrected locations, thereby maintaining or improving the reliability of the memory device and enhancing yield.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional fabrication processes are used without reticle adjustment, then manufacturing simplicity is maintained, but block bending errors occur causing features to deviate from intended locations

Engineering Contradiction:

Improveplacement accuracy of memory cell pillars and conductive structuresVSAvoidcomplexity of fabrication process

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The reticle is adjusted before the fabrication process to compensate for anticipated block bending errors. By pre-modifying the reticle pattern based on predicted stress-induced deformations, the final fabricated features align with their intended locations despite subsequent block bending during manufacturing.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The reticle adjustment applies a counteracting transformation to compensate for the harmful block bending effect. The reticle pattern is deliberately distorted in the opposite direction of the expected block bending, so that when the block bends during fabrication, the features end up at their correct intended positions.

Inventive Principle:

Principle #9Preliminary anti-action

2Manufacturing precision

If reticle adjustments are performed to compensate for block bending errors, then manufacturing precision is improved, but process complexity increases

Engineering Contradiction:

Improveplacement accuracy of sub-block dividers and conductive structuresVSAvoidcomplexity of reticle adjustment process

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The reticle adjustment process modifies geometric parameters of the reticle pattern, such as the positions and dimensions of features, to compensate for block bending. By changing these parameters systematically based on stress models, the fabrication process achieves higher precision without requiring fundamentally new manufacturing techniques.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20230058170A1Memory device structure and forming method including reticle adjustment

Publication Date: 2023.02.23 MICRON TECHNOLOGY INC

AI summary

Some embodiments include apparatuses and methods of forming the apparatuses. One of the apparatuses includes memory cell strings having respective pillars extending through levels of first conductive materials interleaved with levels of first dielectric materials; conductive structures formed over the memory cell strings and extending through levels of second conductive materials interleaved with levels of second dielectric materials; dielectric structures located in respective trenches over the memory cell strings and dividing the levels of second conductive materials into portions that are electrically separated from each other; and the dielectric structures located such that the distance between two adjacent dielectric structures is different from the distance between two other adjacent dielectric structures.