Continuous Chemical Bath Wetdeck Process for Semiconductor Wafer Cleaning

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Solution Overview

Problem

Semiconductor wetdeck processes face inefficiencies due to the degradation of chemical bath solutions over time, leading to reduced effectiveness and the need for frequent solution changes, which incur downtime and additional costs.

Innovation Solution

A system and method that continuously adds fresh chemicals to and purges spent chemicals from the bath, using a fresh chemical source and chemical purge unit controlled by sensors to maintain optimal chemical concentrations and levels, thereby extending the effective working life of the chemical bath.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If the chemical bath is used continuously without replacement, then operational time is extended, but chemical effectiveness deteriorates

Engineering Contradiction:

Improvechemical bath operational lifeVSAvoidchemical effectiveness

Core Design Contradiction:

Duration of action of stationary objectVSReliability

Solution Approach 1:

The system continuously monitors chemical parameters (concentration, temperature, pH) and adjusts them to maintain effectiveness. Fresh chemicals are added and spent chemicals are removed based on real-time parameter measurements, allowing the bath to operate continuously without effectiveness degradation

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The chemical bath operates continuously with uninterrupted wafer processing. The system maintains chemical effectiveness through continuous monitoring and adjustment, eliminating the need to stop production for solution changes while preserving cleaning performance

Inventive Principle:

Principle #20Continuity of useful action

2Reliability

If the chemical bath is replaced frequently to maintain effectiveness, then chemical effectiveness is maintained, but downtime increases

Engineering Contradiction:

Improvechemical effectivenessVSAvoiddowntime for solution change

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The chemical bath remains in continuous operation without draining or replacement. Sensors monitor chemical degradation in real-time and trigger automatic replenishment of fresh chemicals, ensuring uninterrupted wafer processing and eliminating solution change downtime

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The system automatically monitors and replenishes chemical bath composition without manual intervention. When chemicals degrade, the system self-corrects by adding fresh chemicals and removing spent ones, maintaining effectiveness continuously without requiring operator action or production stoppage

Inventive Principle:

Principle #25Self-service

3Reliability

If fresh chemicals are continuously added to the bath, then chemical effectiveness is maintained, but chemical cost increases

Engineering Contradiction:

Improvechemical effectivenessVSAvoidchemical consumption

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

Sensors continuously measure chemical concentration, temperature, and other parameters in the bath. This feedback information is used to control the precise addition of fresh chemicals and removal of spent chemicals, ensuring chemicals are replenished only when needed and minimizing waste

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system monitors and adjusts chemical parameters to optimize bath composition. By maintaining parameters within optimal ranges and only replenishing chemicals when degradation is detected, the system prevents both over-consumption and under-maintenance of chemical effectiveness

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8287751B1System and method for providing a continuous bath wetdeck process

Publication Date: 2012.10.16 NAT SEMICON CORP

AI summary

A system and method is described for providing a continuous bath wetdeck process for use in the manufacture of semiconductor wafers. The invention provides a method for extending an effective working life of a chemical bath of the type that comprises a chemical bath liquid within a chemical bath container. An amount of fresh chemical is continuously added to the chemical bath liquid and an amount of chemical bath liquid is simultaneously purged from the chemical bath container. A balance is maintained between the amount of fresh chemical that is added to the chemical bath liquid and the amount of chemical bath liquid that is purged in order to maintain the effectiveness of the chemical bath liquid to clean semiconductor wafers within the chemical bath.