Surface Cleaning Method Using Spray and Free Flow Steps

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Solution Overview

Problem

Existing methods for cleaning plate-like articles, such as semiconductor wafers, face a dilemma where high mechanical energy is required for effective particle removal, leading to surface damage, especially as structures become smaller.

Innovation Solution

A cleaning method involving a sequence of free flow and spray cleaning steps, using specific nozzle configurations and cleaning liquids, with overlapping steps to maintain surface wetness and minimize stress, significantly enhances particle removal efficiency without increasing damage to the surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high mechanical energy is applied to remove particles, then particle removal efficiency is improved, but surface damage increases

Engineering Contradiction:
Improveparticle removal efficiencyVSAvoidsurface damage
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The cleaning process is segmented into multiple sequential steps with different cleaning mechanisms (e.g., spray cleaning, contact cleaning, rinsing). Each step performs a specific function at a controlled energy level, avoiding the need for single high-energy treatment that causes surface damage while achieving cumulative particle removal effectiveness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cleaning method employs periodic alternation between different cleaning modes (high-energy spray phases followed by lower-energy contact cleaning phases). This periodic action allows particle removal during high-energy phases while limiting surface damage through subsequent gentler phases, creating a cyclical process that balances effectiveness with surface protection.

Inventive Principle:
Principle #19Periodic action

2Productivity

If mechanical agitation is increased for particle removal, then cleaning effectiveness improves, but stress on surface structures increases

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidstress on surface structures
Core Design Contradiction:
ProductivityVSStress or pressure

Solution Approach 1:

Different regions of the surface receive different types and intensities of cleaning treatment. Areas with higher particle contamination or greater tolerance receive more aggressive cleaning, while sensitive structured areas receive gentler treatment. This localized differentiation allows effective particle removal where needed while protecting critical surface structures from excessive stress.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The cleaning process dynamically adjusts parameters such as liquid flow rate, pressure, temperature, and chemical composition across different cleaning steps. By changing these parameters sequentially rather than maintaining constant high values, the process achieves effective particle removal while keeping stress on surface structures within acceptable limits at any given moment.

Inventive Principle:
Principle #35Parameter changes

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 increases particle removal efficiency by over 20% without altering process parameters or overall time, effectively addressing the challenge of surface damage while maintaining surface integrity.

Implementation Method 1

treating the surface with spray cleaning, wherein liquid is directed through a spray nozzle towards the surface in form of droplets

Methodology Applied
Scientific EffectSpray: Spray

Implementation Method 2

treating the surface with free flow cleaning, wherein liquid is dispensed through a dispense nozzle onto the surface in a continuous liquid flow

Methodology Applied
Scientific EffectFluid flow:

Data Source

PatentUS8932408B2Method for cleaning a surface
Publication Date: 2015.01.13 LAM RES AG

AI summary

A method for cleaning a surface of a plate-like article includes the steps of:treating the surface with free flow cleaning, wherein liquid is dispensed through a dispense nozzle onto the surface in a continuous liquid flow, andtreating the surface with spray cleaning, wherein liquid is directed through a spray nozzle towards the surface in form of droplets. The surface is treated with a spray cleaning step before the free flow cleaning step and a spray cleaning step after the free flow cleaning step.