Reticle Cleaning System Static Charge Neutralization

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Solution Overview

Problem

The scaling down of semiconductor devices increases manufacturing complexity, with tiny defects on reticles during cleaning processes, particularly due to electrostatic discharge (ESD) caused by static charges accumulated during the spin dry process, leading to pattern damage on reticles.

Innovation Solution

A reticle cleaning system with integrated static charge detecting and removing functions, including an ionizer to produce ionized air molecules, a fluid generator to control humidity, and a static charge sensor to monitor and adjust conditions, which reduces static charges on reticles by ionizing air molecules and maintaining optimal humidity levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the spin dry process is used to clean reticles, then cleaning efficiency is improved, but static charge accumulation occurs leading to electrostatic discharge and pattern damage

Engineering Contradiction:

Improvecleaning efficiencyVSAvoidelectrostatic discharge

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The ionizer is activated before the spin dry process to pre-ionize the air and reduce static charge accumulation on the reticle surface during cleaning, preventing electrostatic discharge before it occurs

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Ionized air molecules serve as an intermediary between the ionizer and the reticle surface, neutralizing static charges through ion-air-reticle interaction, thereby preventing direct electrostatic discharge damage to the pattern

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If humidity control is implemented during reticle cleaning, then static charge accumulation is reduced, but system complexity increases

Engineering Contradiction:

Improvestatic charge accumulationVSAvoidsystem complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The humidity of the cleaning environment is controlled within a specific range (40-60% relative humidity) to optimize the balance between static charge prevention and system simplicity, using humidity as a controllable parameter to reduce electrostatic effects

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

Effectively minimizes electrostatic discharge occurrences during reticle cleaning, ensuring pattern integrity by actively detecting and neutralizing static charges and maintaining a humidity environment that inhibits static charge accumulation, thus enhancing the reliability of semiconductor manufacturing processes.

Implementation Method 1

an ionizer to produce ionized air molecules

Methodology Applied

Scientific EffectIonization: Ionisation

Implementation Method 2

a fluid generator to control humidity

Methodology Applied

Scientific EffectHumidity control:

Data Source

PatentUS11675264B2Reticle cleaning system

Publication Date: 2023.06.13 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A reticle cleaning system includes a casing, a reticle holder, and a static charge reducing device. The reticle holder is in the casing and configured to hold a reticle. The static charge reducing device is above the reticle holder and includes a fluid generator, an ionizer, and a static charge sensor. The fluid generator is configured to control a humidity condition in the casing. The ionizer is configured to provide ionized air molecules to the reticle. The static charge sensor is configured to detect a static charge value on the reticle, wherein the ionizer is between the fluid generator and the static charge sensor.