Substrate Etching Bath Flow Modulation for Uniform Multi-Wafer Processing

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Solution Overview

Problem

Existing substrate processing techniques face issues with uniformity due to stagnation of liquid flow and galvanic corrosion, leading to abnormal regions with reduced etching amounts during the etching of multiple substrates simultaneously.

Innovation Solution

A substrate processing apparatus with adjustable flow rate controllers for processing liquid discharge, which intentionally disturbs liquid flow to prevent stagnation and restricts gas supply to reduce galvanic corrosion, ensuring uniform etching across all substrates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple substrates are etched en bloc by immersing them in a processing liquid, then productivity is improved, but liquid flow stagnation occurs leading to non-uniform etching

Engineering Contradiction:

Improveetching throughputVSAvoidetching uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies dynamics by making the liquid flow system movable and adjustable. Multiple discharge openings are provided with independent flow rate controllers that can dynamically adjust the flow rate of processing liquid discharged from each opening. This dynamic control prevents stagnation by continuously varying the flow patterns, ensuring uniform etching while maintaining high productivity through en bloc processing of multiple substrates.

Inventive Principle:

Principle #15Dynamics

2Device complexity

If processing liquid is discharged from fixed discharge openings, then device complexity is reduced, but liquid flow stagnation occurs causing abnormal regions with reduced etching amounts

Engineering Contradiction:

Improvedischarge system structureVSAvoidetching uniformity

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent transforms a static discharge system into a dynamic one by equipping each discharge opening with an independent flow rate controller. This allows the system to adapt flow rates dynamically during etching processing, preventing liquid flow stagnation and ensuring uniform etching across all substrates without requiring overly complex structural modifications.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent applies parameter changes by independently controlling the flow rate parameter for each discharge opening. The flow rate controllers adjust the flow rate of processing liquid discharged from respective openings, changing this critical parameter to prevent stagnation and ensure uniform etching distribution across multiple substrates processed en bloc.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If gas supply is restricted to reduce galvanic corrosion, then reliability is improved, but etching uniformity may be affected

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidetching uniformity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent converts the potentially harmful effect of gas supply into a beneficial control mechanism. By carefully managing gas supply during etching processing, the system prevents galvanic corrosion between different metal layers on substrates while maintaining etching uniformity. The flow rate controllers work in conjunction with gas supply management to achieve both corrosion prevention and uniform etching results.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 apparatus enhances etching uniformity by preventing stagnation and reducing galvanic corrosion, resulting in consistent etching across all substrates and improved processing efficiency.

Implementation Method 1

The first discharge opening group and the second discharge opening group are disposed under the multiple substrates within the processing tub, and configured to discharge the processing liquid into the processing tub

Methodology Applied

Scientific EffectFluid flow:

Implementation Method 2

The first adjusting device is configured to change a flow rate of the processing liquid discharged from the first discharge opening group. The second adjusting device is configured to change a flow rate of the processing liquid discharged from the second discharge opening group

Methodology Applied

Scientific EffectFlow rate control:

Data Source

PatentUS11972958B2Substrate processing apparatus and substrate processing method

Publication Date: 2024.04.30 TOKYO ELECTRON LTD

AI summary

A substrate processing apparatus includes a processing tub configured to perform an etching processing therein by immersing multiple substrates in a processing liquid; a first and second discharge opening groups disposed under the substrates within the processing tub, and configured to discharge the processing liquid into the processing tub; a first adjusting device configured to change a flow rate of the processing liquid discharged from the first discharge opening group; a second adjusting device configured to change a flow rate of the processing liquid discharged from the second discharge opening group; a controller configured to control the first and second adjusting devices to perform, during the etching processing, a flow rate adjusting processing of increasing and decreasing the flow rate of the processing liquid discharged from the first discharge opening group and the flow rate of the processing liquid discharged from the second discharge opening group to different values.