Magnetizing Apparatus for MRAM Wafer Contamination Control

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Solution Overview

Problem

The contamination of semiconductor wafers during the magnetic annealing process in magnetic random access memory (MRAM) manufacturing, which affects the reliability of the magnetic film, due to dust generated during the transfer of wafers from storage containers to magnetic field generating units.

Innovation Solution

A magnetizing apparatus with a sealed storage container made of non-magnetic material, conveyed in a sealed state from a placing table to a magnetizing chamber, where a magnetic field is applied at room temperature using a solenoid magnet, minimizing exposure to the environment and reducing contamination risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If wafers are transferred from storage containers to magnetic field generating units, then the magnetic annealing process can be performed, but dust is generated causing contamination of the wafers

Engineering Contradiction:

Improvewafer contaminationVSAvoidtransfer equipment

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the storage container and the magnetic field generating unit into a single integrated apparatus. The storage container is designed to be directly placed inside the magnetic field generating unit, eliminating the need for separate transfer equipment. This merging of functions allows wafers to remain in the storage container throughout the magnetic annealing process, preventing dust contamination while avoiding complex transfer mechanisms.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The storage container serves as an intermediary that allows the magnetic field to pass through while protecting the wafers inside. The container is designed with non-magnetic material that permits magnetic field penetration, enabling the magnetic annealing process to occur on wafers that remain enclosed in the container, thus avoiding direct exposure to dust-generating transfer operations.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If wafers are exposed to environment during transfer, then transfer operations can be performed, but contamination risk increases

Engineering Contradiction:

Improvewafer transferVSAvoidcontamination

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The magnetic field is applied to the wafers while they are still in the storage container, before any transfer operation is needed. This preliminary action allows the magnetic annealing process to be completed in advance, eliminating the need for subsequent transfer operations that would expose wafers to environmental contamination.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The storage container is designed as a non-magnetic enclosure that acts as a protective shell, allowing the magnetic field to penetrate through it while keeping the wafers isolated from the external environment. This flexible shielding approach maintains ease of operation by allowing direct placement of the container inside the magnetic field generating unit, while simultaneously preventing contamination.

Inventive Principle:

Principle #30Flexible shells and thin films

3Reliability

If inert gas facilities are used to prevent contamination, then substrate protection is improved, but manufacturing cost increases

Engineering Contradiction:

Improvesubstrate protectionVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent extracts the requirement for inert gas facilities by redesigning the process to eliminate the need for complex transfer operations. By allowing the storage container to be directly placed inside the magnetic field generating unit and performing magnetic annealing on the wafers while they remain in the container, the system removes the necessity for expensive inert gas protection infrastructure.

Inventive Principle:

Principle #2Taking out (Extraction)

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

The solution effectively suppresses contamination of substrates, enhances the reliability of MRAM manufacturing, reduces the need for inert gas facilities, and decreases manufacturing costs and time by eliminating the requirement for wafer transfer and associated equipment.

Implementation Method 1

a magnetizing chamber configured to accommodate the storage container and apply a magnetic field to the plurality of substrates in the storage container

Methodology Applied

Scientific EffectMagnetic field generation: Electromagnet

Implementation Method 2

applying a magnetic field at room temperature using a solenoid magnet

Methodology Applied

Scientific EffectSolenoid effect: Solenoid

Data Source

PatentUS10096416B2Magnetizing apparatus and magnetizing method

Publication Date: 2018.10.09 TOKYO ELECTRON LTD

AI summary

Disclosed is a magnetizing apparatus including: a placing table configured to place thereon a storage container storing a plurality of substrates; a magnetizing chamber configured to accommodate the storage container and apply a magnetic field to the plurality of substrates in the storage container; and a conveying mechanism configured to convey the storage container from the placing table into the magnetizing chamber.