Substrate Storage Method for Wafer Processing Apparatus

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Solution Overview

Problem

The existing substrate processing methods face challenges in extending the service life of devices formed on wafers due to defects or changes in characteristics caused by prolonged storage of processed wafers, especially when mixed with unprocessed wafers, and inefficiencies in N2 purging within temporary storage areas.

Innovation Solution

A substrate storing method that involves a substrate processing apparatus with a process module, first and second substrate storing containers, and a transferring module, where unprocessed wafers are conveyed from the first container to the second, then to the process module for processing, and processed wafers are returned to the first container after N2 purging in the load ports to prevent mixing and extend the service life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If processed wafers are temporarily stored in a storage area to avoid mixing with unprocessed wafers, then wafer mixture is prevented, but the service life of devices on wafers is reduced due to prolonged storage time

Engineering Contradiction:

Improveprevention of wafer mixtureVSAvoidservice life of device on wafer

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent extracts the harmful factor (processed wafers) from the storage area and directly returns them to the load port FOUP after processing. This eliminates the need for temporary storage in the storage area, thereby preventing wafer mixture while minimizing storage time and extending device service life.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of the conventional flow where processed wafers go to storage area first and then to load port, the patent inverts this sequence by directly returning processed wafers to the load port FOUP. This reversal of the wafer flow path solves the contradiction by eliminating unnecessary storage time while maintaining proper wafer separation.

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If processed wafers are kept in the storage area for longer time, then wafer mixture prevention is maintained, but defects and characteristic changes occur more frequently

Engineering Contradiction:

Improvewafer mixture preventionVSAvoiddefects and characteristic changes

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements a direct return path that allows processed wafers to skip the prolonged storage phase and quickly return to the load port FOUP. This rushing through the processing cycle minimizes the time wafers are exposed to harmful environmental factors, thereby reducing defects and characteristic changes while maintaining mixture prevention.

Inventive Principle:

Principle #21Skipping (Rushing through)

Solution Approach 2:

The system performs preliminary N2 purging of the load port FOUP before returning processed wafers, creating a protective atmosphere in advance. This preliminary action prepares a safe environment that prevents defects and characteristic changes during the brief transfer and storage period at the load port.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If N2 purging is performed in the storage area, then atmosphere improvement is achieved, but the effectiveness is reduced compared to localized purging in the FOUP

Engineering Contradiction:

ImproveN2 purging effectivenessVSAvoidN2 gas consumption efficiency

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent applies N2 purging locally at the load port FOUP rather than in the entire storage area. This localized approach concentrates the purging effect where it is most needed (at the load port where wafers are actively handled), maximizing effectiveness while minimizing N2 gas consumption and energy loss.

Inventive Principle:

Principle #3Local quality

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 method effectively extends the service life of devices on wafers by minimizing storage time in the temporary area, improving throughput by allowing processed wafers to be returned to a N2-purged environment, thus reducing defects and maintaining device characteristics.

Implementation Method 1

introducing inactive gas into the first substrate storing container

Methodology Applied

Scientific EffectN2 purging:

Data Source

PatentUS10553468B2Substrate storing method and substrate processing apparatus

Publication Date: 2020.02.04 TOKYO ELECTRON LTD

AI summary

A substrate processing apparatus includes a process module in which a substrate is processed, a first substrate storing container, a second substrate storing container, and a transferring module that conveys the substrate between locations connected by the transferring module, wherein the process module, the first substrate storing container, and the second substrate storing container are connected by the transferring module, the method including the successive steps of, conveying an unprocessed substrate stored in the first substrate storing container to the second substrate container, conveying the unprocessed substrate stored in the second substrate storing container to the process module to process the unprocessed substrate, conveying the processed substrate processed in the process module to the first substrate storing container, and introducing inactive gas into the first substrate storing container.