Semiconductor Transfer Chamber Nitrogen Inerting

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Solution Overview

Problem

The existing wafer transfer systems in semiconductor production fail to maintain a low partial pressure of oxidation gases, such as oxygen, during the transfer of wafers between containers and processing chambers, leading to potential oxidation of wafer surfaces and contamination issues.

Innovation Solution

A transfer system is designed with separate inert-gas supply and discharge systems for each chamber, using nitrogen to maintain a controlled environment, and a shutter mechanism to isolate the clean air supply, ensuring the inert gas is only used when necessary and minimizing exposure to potential contaminants like boron from the filter units.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a fan filter unit supplies clean air into the chamber where wafer transfer occurs, then the air is purified from dust and particles, but oxygen and moisture in the air can oxidize the wafer surface

Engineering Contradiction:

Improvewafer surface qualityVSAvoidoxidation of wafer surface

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an inert gas (nitrogen) supply system that supplies nitrogen gas into the chamber where wafer transfer occurs. The inert gas displaces oxygen-containing air from the chamber, creating an oxygen-free environment that prevents wafer surface oxidation during transfer operations. This directly resolves the contradiction by replacing the harmful oxygenated air with benign inert gas.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

2Object-affected harmful factors

If nitrogen is continuously supplied into the chamber to prevent oxidation, then wafer surface oxidation is prevented, but the amount of nitrogen used increases significantly

Engineering Contradiction:

Improveoxidation preventionVSAvoidnitrogen consumption

Core Design Contradiction:

Object-affected harmful factorsVSLoss of substance

Solution Approach 1:

The patent implements periodic nitrogen supply rather than continuous supply. The nitrogen supply is activated only during wafer transfer operations when oxidation risk exists, and deactivated when wafers are stored in sealed pods or containers. This periodic operation maintains oxidation protection while dramatically reducing nitrogen consumption compared to continuous supply.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent supplies nitrogen gas in advance into pods and containers before wafer transfer operations begin. This preliminary nitrogen filling creates a protective atmosphere inside the storage vessels, so that when wafers are transferred, they are already in an oxygen-free environment, eliminating the need for continuous nitrogen supply during transfer.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If the pod opening faces the mini-environment for easy wafer transfer, then transfer efficiency is improved, but oxidation gas from the mini-environment can enter the pod

Engineering Contradiction:

Improvewafer transfer efficiencyVSAvoidoxidation gas entry into pod

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent fills the pod interior with inert nitrogen gas before transfer operations. When the pod opening faces the mini-environment during transfer, the nitrogen atmosphere inside the pod creates a pressure barrier that prevents oxidation-containing air from the mini-environment from entering the pod, thus protecting wafers while maintaining transfer efficiency.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

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 system effectively reduces oxidation of wafer surfaces and minimizes contamination by maintaining a low partial pressure of oxidation gases and reducing the amount of nitrogen used, thereby preventing impurities from affecting semiconductor performance.

Implementation Method 1

a fan filter unit capable of supplying clean air into a first chamber disposed above the first chamber

Methodology Applied

Scientific EffectAir supply and filtration: Filter (physical)

Implementation Method 2

a first inert-gas supply system that is disposed above the first chamber dependently from the fan filter unit and capable of supplying inert gas into the first chamber

Methodology Applied

Scientific EffectInert gas atmosphere control:

Implementation Method 3

a first discharge system capable of discharging gas existing in the first chamber

Methodology Applied

Scientific EffectGas discharge:

Data Source

PatentUS8083456B2Contained object transfer system

Publication Date: 2011.12.27 TDK CORP

AI summary

A so-called transfer chamber in a semiconductor processing apparatus in which an FIMS system is secured is separated into a second chamber in which a transfer robot is disposed and a first chamber that is minute and includes a door capable of holding a cap of a pod as the FIMS system. In the second chamber, higher pressure than in the first chamber is maintained by a minute amount of nitrogen. In the first chamber, usually, a down flow of clean air is used via the FFU. When the wafer is transferred, a down flow of nitrogen is used. Thus, oxidation gas in the transfer chamber and released substances caused the FFU can be decreased.