Substrate Cleaning Apparatus Using Sequential Acidic and Basic Chemical Stages

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Solution Overview

Problem

Conventional substrate processing apparatuses are inadequate in effectively cleaning substrates after polishing, particularly with cerium oxide, due to insufficient removal rates and the risk of water marks during drying, which can fix cerium oxide to the substrate.

Innovation Solution

A substrate processing apparatus and method that includes a polisher, a first cleaner using sulfuric acid and hydrogen peroxide water, a second cleaner using a basic chemical liquid and hydrogen peroxide water, and a drier, allowing for sequential cleaning and drying processes to efficiently remove cerium oxide without drying the substrate before cleaning, thereby preventing water marks and improving cleaning effectiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the substrate is dried before cleaning, then the cleaning process can be performed separately, but water marks are generated and cerium oxide is fixed to the substrate

Engineering Contradiction:

Improvecleaning effectivenessVSAvoidwater marks and cerium oxide fixation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The substrate is cleaned immediately after polishing while still wet, before any drying occurs. This preliminary cleaning action prevents water marks and cerium oxide fixation by removing contaminants before the substrate surface dries and bonds them permanently.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The cleaning process is performed continuously without interruption or drying step between polishing and cleaning. The substrate transitions directly from polishing to cleaning in a continuous workflow, maintaining the wet state that prevents harmful fixation of cerium oxide.

Inventive Principle:

Principle #20Continuity of useful action

2Reliability

If multiple cleaning processes are used, then cleaning effectiveness is improved, but total processing time increases

Engineering Contradiction:

Improvecleaning effectivenessVSAvoidtotal processing time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The cleaning process is divided into two distinct stages: first cleaning with sulfuric acid and hydrogen peroxide to remove polishing residues, then second cleaning with basic chemical liquid and hydrogen peroxide to remove any remaining contaminants. This segmentation allows each cleaning stage to target specific types of contamination efficiently.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cleaning process utilizes parameter changes by switching between acidic and basic chemical environments. The first cleaner uses acidic conditions (sulfuric acid) to dissolve certain residues, while the second cleaner uses basic conditions to remove other types of contaminants, optimizing removal effectiveness for different substances.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If cerium oxide is not removed thoroughly, then the cleaning process is simpler, but the substrate quality deteriorates

Engineering Contradiction:

Improvecleaning process complexityVSAvoidsubstrate quality

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

Hydrogen peroxide is used as an intermediary chemical in both cleaning stages. It acts as a powerful oxidizing agent that enhances the cleaning capability of both acidic and basic solutions, enabling thorough removal of cerium oxide and other contaminants while maintaining substrate integrity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The cleaning system uses composite chemical approaches by combining different chemical agents (sulfuric acid, basic chemical liquid, and hydrogen peroxide) in sequential cleaning stages. This composite cleaning strategy addresses multiple types of contamination that would be difficult to remove with a single chemical approach.

Inventive Principle:

Principle #40Composite materials

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 and method enable thorough cleaning of substrates with a reduced number of processes, shortening total processing time, and reliably removing cerium oxide, while preventing water marks and improving cleaning power by avoiding drying before cleaning.

Implementation Method 1

a first cleaner configured to clean, using sulfuric acid and hydrogen peroxide water, the substrate polished by the polisher

Methodology Applied

Scientific EffectChemical cleaning:

Implementation Method 2

a second cleaner configured to clean, using a basic chemical liquid and hydrogen peroxide water, the substrate cleaned by the first cleaner

Methodology Applied

Scientific EffectChemical cleaning:

Implementation Method 3

a drier configured to dry the substrate cleaned by the second cleaner

Methodology Applied

Scientific EffectDrying:

Data Source

PatentUS10500691B2Substrate processing apparatus and substrate processing method

Publication Date: 2019.12.10 EBARA CORP

AI summary

A substrate processing apparatus includes a polisher configured to polish a substrate using a polishing liquid, a first cleaner configured to clean the substrate polished by the polisher using sulfuric acid and hydrogen peroxide water, a second cleaner configured to clean the substrate cleaned by the first cleaner using a basic chemical liquid and hydrogen peroxide water, and a drier configured to dry the substrate cleaned by the second cleaner.