Nitrogen Purging Front-End Interface Unit Wafer Deposition

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Solution Overview

Problem

The scaling down of IC transistor sizes leads to increased resistance values and performance degradation due to exposure to oxygen and moisture during processing, resulting in higher contact resistance and yield loss.

Innovation Solution

The use of nitrogen purging in the front-end interface unit and wafer holder to minimize exposure to oxygen and moisture during the metal deposition process, ensuring a controlled environment for wafer processing in the deposition tool.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If transistor size is scaled down to increase functional density, then production efficiency is improved, but resistance values increase and performance degrades

Engineering Contradiction:

Improveproduction efficiencyVSAvoidtransistor performance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies inert atmosphere by purging the front-end interface unit and wafer holder with nitrogen gas to create an oxygen-free environment. This prevents oxidation of the wafer and deposited metal layers during the deposition process, thereby maintaining low contact resistance and preventing performance degradation in scaled-down transistors while enabling continued production efficiency gains

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

2Ease of operation

If wafer is exposed to ambient environment during processing, then ease of operation is improved, but oxygen and moisture absorption increases causing yield loss

Engineering Contradiction:

Improvewafer handling convenienceVSAvoidwafer quality

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The system maintains an inert nitrogen atmosphere in the front-end interface unit and wafer holder throughout the wafer handling and deposition process. This allows automated wafer processing to continue while preventing oxygen and moisture absorption, thereby eliminating yield loss from oxidation without complicating the operational workflow

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

Nitrogen gas serves as an intermediary substance that fills the front-end interface unit and wafer holder, acting as a barrier between the wafer and ambient air. This intermediary inert atmosphere enables easy wafer handling while simultaneously protecting the wafer from harmful oxygen and moisture exposure

Inventive Principle:

Principle #24Intermediary (Mediator)

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 reduces the increase in source/drain contact resistance and prevents yield loss by maintaining a dry and oxygen-free environment, enhancing the integrity of the deposited metal layers and silicide regions.

Implementation Method 1

purging the front-end interface unit with nitrogen

Methodology Applied

Scientific EffectNitrogen purging:

Implementation Method 2

depositing a metal layer on the wafer in the deposition tool

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Data Source

PatentUS10269926B2Purging deposition tools to reduce oxygen and moisture in wafers

Publication Date: 2019.04.23 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A method includes placing a wafer in a wafer holder, placing the wafer holder on a loadport of a deposition tool, connecting the wafer holder to a front-end interface unit of the deposition tool, purging the front-end interface unit with nitrogen, and depositing a metal layer on the wafer in the deposition tool.