Substrate Stage Gas Diffusion for Precise Wafer Temperature Control

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Solution Overview

Problem

Existing substrate processing technologies face challenges in accurately controlling temperature distribution across substrates, particularly in creating a steep pressure difference between the central and peripheral regions, which affects etching rates and process characteristics.

Innovation Solution

A substrate stage design featuring an annular conductance band that divides the mounting surface into outer and inner regions, with specific protrusions and flow paths for heat transfer gas, allowing for controlled pressure differences and diffusion of gas along the circumferential direction to manage temperature distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a circular partition wall is provided on the substrate mounting surface to make heat transfer gas circulate below the substrate, then temperature control is improved, but the pressure difference between central and peripheral regions cannot be sufficiently increased

Engineering Contradiction:

Improvetemperature control accuracyVSAvoidpressure difference between central and peripheral regions

Core Design Contradiction:

TemperatureVSStress or pressure

Solution Approach 1:

The partition wall is segmented into multiple regions (first partition wall region, second partition wall region, third partition wall region) with different heights and configurations. This segmentation allows different gas flow paths and pressure distributions in different regions, enabling both temperature control and sufficient pressure difference between central and peripheral regions of the substrate.

Inventive Principle:

Principle #1Segmentation

2Stress or pressure

If the partition wall height is increased to create larger pressure difference, then pressure control is improved, but gas flow uniformity and temperature distribution are adversely affected

Engineering Contradiction:

Improvepressure differenceVSAvoidtemperature distribution uniformity

Core Design Contradiction:

Stress or pressureVSTemperature

Solution Approach 1:

Different regions of the partition wall have different heights and configurations tailored to local requirements. The first partition wall region has a first height, the second region has a second height, and the third region has a third height. This local quality variation allows optimization of pressure difference in specific regions without compromising overall gas flow uniformity and temperature distribution.

Inventive Principle:

Principle #3Local quality

3Device complexity

If a simple circular partition wall is used, then device complexity is reduced, but the ability to control etching rates and process characteristics is insufficient

Engineering Contradiction:

Improvepartition wall structureVSAvoidetching rate control precision

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The partition wall is divided into multiple segmented regions with different heights and configurations. This segmentation creates distinct gas flow paths and pressure zones that enable precise control of etching rates and process characteristics across different regions of the substrate, achieving high manufacturing precision without excessive complexity.

Inventive Principle:

Principle #1Segmentation

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 design enhances the accuracy of temperature control across substrates by creating a sharp pressure difference between regions, improving the control of process characteristics such as etching rates and ensuring uniform pressure distribution.

Implementation Method 1

an outer flow path provided in the base portion and in communication with the outer region, and configured to allow a heat transfer gas supplied to a space between the substrate and the mounting surface to flow through the outer flow path; an inner flow path provided in the base portion and in communication with the inner region, and configured to allow the heat transfer gas to flow through the inner flow path

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

an annular diffusion portion provided in the base portion and configured to diffuse the heat transfer gas along a circumferential direction of the partition wall

Methodology Applied

Scientific EffectGas diffusion: Diffusion

Implementation Method 3

a plurality of protrusions provided on the mounting surface in the outer region and the inner region and configured to support the substrate with a gap left between an upper end surface of the partition wall and the substrate

Methodology Applied

Scientific EffectPressure difference: Pressure Gradient

Data Source

PatentUS11854843B2Substrate stage, substrate processing apparatus, and temperature control method

Publication Date: 2023.12.26 TOKYO ELECTRON LTD

AI summary

A substrate stage includes: a base portion having a mounting surface; an annular support configured to support a substrate; an annular partition wall configured to divide the mounting surface into an outer region and an inner region in a radial direction of the substrate; a plurality of protrusions provided on the mounting surface and configured to support the substrate with a gap left between an upper end surface of the partition wall and the substrate; an outer flow path in communication with the outer region, and configured to allow a heat transfer gas supplied to a space between the substrate and the mounting surface to flow therethrough; an inner flow path in communication with the inner region, and configured to allow the heat transfer gas to flow therethrough; and an annular diffusion portion configured to diffuse the heat transfer gas along a circumferential direction of the partition wall.