Ion Source Temperature Control via Gas Cooling Interface

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Solution Overview

Problem

Ion source chambers in ion implanters face challenges in maintaining stable temperature control during high-throughput operations, leading to unstable ion beam profiles and particle generation issues due to thermal isolation and overheating, which affects the precision of semiconductor doping.

Innovation Solution

A gas cooling interface is introduced between a cooling plate and the ion source chamber, utilizing a cooling gas to regulate thermal conductance and control the temperature of the chamber, thereby maintaining stable operation and minimizing thermal gradients.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high-throughput operations are performed in the ion source chamber, then productivity is improved, but temperature stability deteriorates due to thermal isolation and overheating

Engineering Contradiction:

ImprovethroughputVSAvoidtemperature stability

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The ion source chamber is segmented into multiple cooling zones with independent temperature control. The chamber wall is divided into discrete cooling sections, each with its own cooling channels, allowing different regions to be cooled to different temperatures to maintain stability during high-throughput operations

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A thermal intermediary system is introduced between the heat-generating plasma region and the chamber wall. This includes thermal barriers and intermediate cooling layers that mediate heat transfer, preventing direct thermal coupling and allowing independent temperature management of the plasma region and chamber structure

Inventive Principle:

Principle #24Intermediary (Mediator)

2Power

If the ion source chamber temperature is increased to improve ion generation, then ion beam current is improved, but particle generation increases due to thermal effects

Engineering Contradiction:

Improveion beam currentVSAvoidparticle generation

Core Design Contradiction:

PowerVSObject-generated harmful factors

Solution Approach 1:

Different regions of the ion source chamber are maintained at different temperatures optimized for their specific functions. The plasma generation region is kept at higher temperature for efficient ion production, while regions prone to particle generation are maintained at lower temperatures through selective cooling zones

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The temperature parameters of different chamber regions are dynamically adjusted based on operational conditions. During high-current operation, cooling rates and temperatures are modulated to maintain optimal ion generation while suppressing particle formation through precise parameter control

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If thermal isolation is used in the ion source chamber, then ease of manufacture is improved, but temperature control precision deteriorates

Engineering Contradiction:

Improvechamber constructionVSAvoidtemperature control precision

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The mechanical thermal isolation structure is replaced with an active thermal management system. Instead of relying on passive thermal barriers, the system uses controlled cooling channels and thermal conduction paths with adjustable flow rates to achieve precise temperature control while maintaining manufacturing simplicity

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

The gas cooling interface effectively stabilizes the ion source temperature, enhancing the precision of ion implantation and reducing particle generation, ensuring consistent and high-throughput ion beam profiles for semiconductor fabrication.

Implementation Method 1

An interface defined between the plate and the side of the chamber wall receives a gas supplied to the interface at a desired pressure inducing thermal conductance from the interface to the chamber wall

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

A dopant gas is supplied into the ion source chamber. The dopant gas collides with electrons confined within the chamber to generate plasma having desired properties.

Methodology Applied

Scientific EffectIonization: Ionisation

Data Source

PatentUS8183542B2Temperature controlled ion source

Publication Date: 2012.05.22 VARIAN SEMICON EQUIP ASSC INC

AI summary

An ion source is provided that utilizes a cooling plate and a gap interface to control the temperature of an ion source chamber. The gap interface is defined between the cooling plate and a wall of the chamber. A coolant gas is supplied to the interface at a given pressure where the pressure determines thermal conductivity from the cooling plate to the chamber to control the temperature of the interior of the chamber.