Flash Lamp Particle Removal in Heat Treatment Chambers

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Solution Overview

Problem

The existing flash lamp annealing techniques face challenges in accurately removing particles from the heat treatment apparatus, particularly due to the difficulty in eliminating tiny particles that remain after semiconductor wafers crack during intense flash irradiation, which can lead to contamination and treatment failures.

Innovation Solution

A method involving a reduced-pressure atmosphere within the chamber, where multiple flashes of light from a flash lamp are used to discharge particles, combined with a gas flow to efficiently remove particles, and the use of a continuous lighting lamp to generate convection and prevent additional particle formation during treatment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the chamber is opened for maintenance, then accessibility for maintenance is improved, but particles flow into the chamber and remain in large quantities

Engineering Contradiction:

Improvemaintenance accessibilityVSAvoidparticle quantity in chamber

Core Design Contradiction:

Ease of operationVSQuantity of substance

Solution Approach 1:

The patent applies preliminary action by performing flash lamp irradiation to discharge particles from the chamber before semiconductor wafer treatment begins. This preliminary particle removal step ensures that even though particles enter during maintenance, they are eliminated before affecting the actual treatment process, thereby resolving the contradiction between maintenance accessibility and particle contamination.

Inventive Principle:

Principle #10Preliminary action

2Speed

If flash lamp annealing is performed, then heating speed is improved, but semiconductor wafers may crack and generate tiny particles

Engineering Contradiction:

Improveheating speedVSAvoidcrack-induced particles

Core Design Contradiction:

SpeedVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful effect of flash lamp irradiation (which causes wafer cracking and particle generation) into a beneficial particle removal mechanism. By directing flash lamp irradiation toward the chamber walls and ceiling rather than the wafer, the thermal expansion and contraction of chamber components discharges adhering particles, transforming the potential harm into a useful particle elimination function.

Inventive Principle:

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

3Ease of manufacture

If conventional particle removal methods are used, then simplicity is maintained, but particle removal accuracy is insufficient

Engineering Contradiction:

Improveparticle removal simplicityVSAvoidparticle removal accuracy

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent replaces conventional mechanical particle removal methods (such as physical cleaning) with optical field-based flash lamp irradiation. This substitution uses the thermal expansion and contraction effect induced by light to discharge particles, achieving higher removal accuracy while maintaining operational simplicity through automated irradiation sequences.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 approach allows for precise and effective removal of particles from the chamber, reducing the risk of contamination and ensuring higher accuracy in semiconductor wafer treatment by preventing additional particle formation and enhancing the discharge efficiency of particles.

Implementation Method 1

a surface of a semiconductor wafer is increased in temperature in an extremely short time period by irradiation with a flash of light having intense energy

Methodology Applied

Scientific EffectLight heating: Absorption (EM radiation)

Implementation Method 2

while the interior of a chamber of the heat treatment apparatus is placed in a reduced-pressure atmosphere by exhausting gas in the chamber

Methodology Applied

Scientific EffectVacuum exhaustion: Depressurisation

Implementation Method 3

the flying particles are discharged to the outside of the chamber in a flow of nitrogen gas

Methodology Applied

Scientific EffectGas flow transport: Advection

Implementation Method 4

the interior of the chamber is irradiated with a flash of light emitted multiple times from a flash lamp to discharge particles flying in the chamber

Methodology Applied

Scientific EffectPulsed light heating: Absorption (EM radiation)

Data Source

PatentUS10807128B2Particle removal method and heat treatment apparatus

Publication Date: 2020.10.20 SCREEN HOLDINGS CO LTD

AI summary

When a chamber of a heat treatment apparatus is opened for a purpose such as maintenance of the heat treatment apparatus, particles flow in large quantities into the chamber together with an outside atmosphere. After maintenance work is finished, an enclosed space is formed in the chamber and gas in the chamber is exhausted to place the interior of the chamber in a reduced-pressure atmosphere. While the interior of the chamber is in the reduced-pressure atmosphere, the interior of the chamber is irradiated with a flash of light emitted multiple times from a flash lamp to cause momentary gas expansion and subsequent gas shrinkage repeatedly, thereby causing particles adhering in the chamber to fly. The flying particles are discharged from the chamber to remove the particles.