BEOL Planarization for Uniform Metal Thickness and Photo-Key Reading

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Solution Overview

Problem

Conventional planarization techniques for BEOL regions in IC devices result in significant metal loss and non-uniform thickness of metal layers, making it difficult to read sublayer photo-key information accurately, especially for small-pitch interconnects.

Innovation Solution

A method involving selective chemical-mechanical planarization (CMP) followed by non-selective etching (NSE) is employed to form and planarize insulating materials on metal layers, ensuring the insulating material remains within photo keys while minimizing metal loss, thereby maintaining uniform thickness and facilitating accurate sublayer photo-key reading.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If conventional planarization techniques are used for BEOL regions, then planarity is improved, but metal loss increases and thickness uniformity deteriorates

Engineering Contradiction:

ImproveplanarityVSAvoidmetal loss

Core Design Contradiction:

ShapeVSLoss of substance

Solution Approach 1:

The patent applies preliminary action by forming an insulating material layer over the metal layer before planarization. This insulating material serves as a protective preliminary layer that prevents metal loss during the planarization process, while still allowing the planarization to achieve the desired planarity for subsequent photo-key reading.

Inventive Principle:

Principle #10Preliminary action

2Shape

If conventional planarization techniques are used, then planarity is improved, but thickness uniformity worsens

Engineering Contradiction:

ImproveplanarityVSAvoidthickness uniformity

Core Design Contradiction:

ShapeVSManufacturing precision

Solution Approach 1:

The patent applies local quality by selectively removing the insulating material in photo-key regions through selective etching. This creates local variations in the structure: in photo-key areas, the insulating material is removed to expose the metal layer for accurate reading, while in non-photo-key areas, the insulating material remains to maintain planarity and protect the metal layer.

Inventive Principle:

Principle #3Local quality

3Shape

If metal layer thickness is reduced for planarity, then planarity is improved, but photo-key readability deteriorates

Engineering Contradiction:

ImproveplanarityVSAvoidphoto-key readability

Core Design Contradiction:

ShapeVSMeasurement precision

Solution Approach 1:

The patent uses the insulating material as an intermediary layer that mediates between the conflicting requirements of planarity and photo-key readability. The insulating material maintains overall planarity while being selectively removed in photo-key regions, allowing both planarity and readability to coexist through this intermediary structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 achieves precise sublayer photo-key readability and minimal metal loss, enhancing the uniformity and planarity of metal layers, which is crucial for efficient signal routing in IC devices.

Implementation Method 1

selective chemical-mechanical planarization (CMP) followed by non-selective etching (NSE)

Methodology Applied

Scientific EffectChemical-mechanical planarization:

Implementation Method 2

non-selective etching (NSE)

Methodology Applied

Scientific EffectEtching:

Data Source

PatentUS20250372451A1Planarization method for back-end-of-line region of integrated circuit device

Publication Date: 2025.12.04 SAMSUNG ELECTRONICS CO LTD

AI summary

Methods of forming a back-end-of-line (BEOL) region of an integrated circuit (IC) device are provided. A method of forming a BEOL region of an IC device includes forming a metal layer on a lower via. The method includes forming a photo key in an upper portion of the metal layer. The method includes forming an insulating material on the photo key. Moreover, the method includes planarizing the insulating material and the metal layer that includes the photo key.