Semiconductor Process Chamber Cleaning via Plasma Injector

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Solution Overview

Problem

Current semiconductor equipment cleaning methods fail to effectively remove deposits from the process chamber and processing gas injectors, leading to low wafer yield due to particles falling onto wafers.

Innovation Solution

A method involving multiple cleaning steps with nitrogen trifluoride (NF3) gas, using different flux rates and gas combinations, including helium and hydrogen, to generate plasma and clean both the process chamber and processing gas injectors, ensuring thorough removal of deposits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cleaning gas is introduced via specific cleaning gas injectors to clean the process chamber, then the process chamber is cleaned, but the inner walls of the processing gas injectors are not cleaned

Engineering Contradiction:

Improvecleaning effectivenessVSAvoidcleaning coverage

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The processing gas injectors are made to serve dual functions: both as processing gas delivery devices and as cleaning gas injectors. The cleaning gas flows through the same injector structures used for processing, enabling the injectors to clean both themselves and the process chamber, thereby achieving universal functionality.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

Instead of using separate dedicated cleaning gas injectors, the invention reverses the approach by using the processing gas injectors themselves to deliver cleaning gas. This inversion allows the cleaning function to be integrated into the existing processing infrastructure, achieving broader cleaning coverage including the injector inner walls.

Inventive Principle:

Principle #13The other way round (Inversion)

2Productivity

If cleaning gas is introduced at high flux to clean deposits quickly, then cleaning speed is improved, but deposits on processing gas injectors are not effectively removed

Engineering Contradiction:

Improvecleaning speedVSAvoidcleaning completeness

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The cleaning process is divided into distinct sequential steps with different cleaning gas flux levels. A first cleaning step uses high flux for rapid bulk deposit removal, followed by a second cleaning step using low flux for thorough cleaning of injector inner walls, and a third step returns to high flux for final chamber cleaning. This segmentation allows each step to optimize for its specific cleaning target.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cleaning process employs periodic alternation between high flux and low flux cleaning gas introduction. This periodic action allows the system to switch between aggressive bulk cleaning and gentle precision cleaning, ensuring both speed and completeness are achieved at different stages of the cleaning cycle.

Inventive Principle:

Principle #19Periodic action

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 method effectively cleans the process chamber and processing gas injectors, preventing deposits from falling onto wafers, thereby improving wafer yield and productivity.

Implementation Method 1

conducting a cleaning gas into the process chamber via a short processing gas injector for generating a plasma of the cleaning gas in the process chamber

Methodology Applied

Scientific EffectPlasma: Plasma

Implementation Method 2

the NF3 gas is introduced into the process chamber and used to etch the deposits deposited upon a dome and the inner wall of the process chamber

Methodology Applied

Scientific EffectEtching:

Data Source

PatentUS7931752B2Method for cleaning semiconductor equipment

Publication Date: 2011.04.26 UNITED MICROELECTRONICS CORP

AI summary

A method for cleaning a semiconductor equipment is provided. First, a first cleaning step is performed to the process chamber. The first cleaning step includes conducting a cleaning gas into the process chamber via a short processing gas injector for generating a plasma of the cleaning gas in the process chamber. Then, a cleaning step is performed to a long cleaning gas injector. The cleaning step performed to the long cleaning gas injector includes conducting the cleaning gas into the process chamber via the long processing gas injector. Then, a second cleaning step is performed to the process chamber. The second cleaning step includes conducting the plasma of the cleaning gas into the process chamber via the short processing gas injector.