Gas Supply Device Stabilizing Carrier Gas Flow After Tank Replacement

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Solution Overview

Problem

The process reproducibility deteriorates after replacing the film forming raw material tank in tungsten film deposition, leading to non-film formation phenomena and a prolonged time to resume stable process conditions, resulting in extra wafer consumption until reproducibility is obtained.

Innovation Solution

A gas supply device and method that stabilizes the flow rate of the carrier gas using a mass flow controller and flow meter before supplying the raw material gas into the processing vessel, ensuring stable gas supply after tank replacement, including an initial stabilization step to determine flow meter stability before initiating film formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If film formation is performed immediately after replacing the film forming raw material tank, then productivity is maintained, but process reproducibility deteriorates leading to non-film formation phenomena

Engineering Contradiction:

Improvefilm formation efficiencyVSAvoidprocess reproducibility

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system performs preliminary stabilization processing by circulating carrier gas through the raw material container and monitoring flow rate before initiating film formation. This preliminary action ensures the raw material is properly vaporized and the system reaches a stable state, preventing non-film formation phenomena while maintaining productivity.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses a flow meter to continuously monitor the carrier gas flow rate and provides feedback to the control unit. When the flow rate stabilizes within a predetermined range, the system automatically transitions to film formation mode. This feedback mechanism ensures process reproducibility by confirming system stability before production begins.

Inventive Principle:

Principle #23Feedback

2Reliability

If film formation is repeated multiple times after tank replacement to achieve stability, then process reproducibility is improved, but time consumption and wafer usage increase

Engineering Contradiction:

Improveprocess reproducibilityVSAvoidtime to resume process

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system replaces the mechanical trial-and-error approach of repeated film formation with an automated monitoring and control system. The flow meter and control unit automatically detect when the system reaches a stable state, eliminating the need for multiple test runs and reducing time loss while maintaining high process reproducibility.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If film formation is repeated multiple times after tank replacement to achieve stability, then process reproducibility is improved, but wafer consumption increases

Engineering Contradiction:

Improveprocess reproducibilityVSAvoidwafer consumption

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The system performs self-verification by automatically monitoring its own operational parameters (carrier gas flow rate) and determining when it is ready for production. This self-service capability eliminates the need for operator intervention and test wafers, reducing wafer consumption while ensuring process reproducibility.

Inventive Principle:

Principle #25Self-service

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 reduces the time required to achieve stable process reproducibility and minimizes wafer consumption by ensuring the raw material gas is supplied only when the flow meter detection values are stabilized, thereby improving film formation consistency and efficiency.

Implementation Method 1

a mass flow controller connected to an upstream side of the raw material container and configured to control a flow rate of the carrier gas

Methodology Applied

Scientific EffectMass flow control:

Implementation Method 2

a flow meter connected to a downstream side of the raw material container

Methodology Applied

Scientific EffectFlow measurement:

Implementation Method 3

a raw material container having an inner space in which a raw material is vaporized to generate a raw material gas

Methodology Applied

Scientific EffectVaporization: Evaporation

Data Source

PatentUS11155923B2Gas supply device, gas supply method and film forming method

Publication Date: 2021.10.26 TOKYO ELECTRON LTD

AI summary

There is provided a gas supply device for vaporizing a raw material inside a raw material container and supplying a raw material gas into a processing vessel together with a carrier gas, including: a mass flow controller connected to an upstream side of the raw material container and configured to control a flow rate of the carrier gas; a flow meter connected to a downstream side of the raw material container; and a control part configured to perform a control so as not to supply the raw material gas into the processing vessel until a detection value of the flow meter with respect to the carrier gas controlled to have a constant flow rate by the mass flow controller is stabilized after replacing the raw material container.