Substrate Supporting Unit Shaft Heater for Temperature Uniformity

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Solution Overview

Problem

Existing substrate supporting units face challenges in maintaining uniform temperature across the substrate during high-temperature semiconductor processes, leading to variations in thin film properties due to heat loss through the shaft and non-uniform heater density.

Innovation Solution

Incorporation of a first heater along the shaft and a second heater on the stage, with the first heater densely arranged on the flange and connector to prevent heat loss and ensure uniform heating, along with an electrostatic chuck for precise substrate fixation and optional helium gas flow for enhanced thermal conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a heater is installed on the stage to control substrate temperature, then temperature control capability is improved, but heat loss through the shaft causes temperature non-uniformity

Engineering Contradiction:
Improvesubstrate temperature controlVSAvoidheat loss through shaft
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The heating system is segmented into two independent heater units: a first heater installed on the shaft and a second heater installed on the stage. This segmentation allows each heater to address specific thermal zones, with the first heater compensating for heat loss through the shaft and the second heater providing direct stage heating, thereby resolving the temperature non-uniformity caused by shaft heat loss.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first heater on the shaft acts as an intermediary heating element that compensates for thermal energy lost through the shaft structure. By introducing this intermediate heating source, the system recovers heat that would otherwise be lost, maintaining temperature uniformity between the shaft and stage without requiring excessive power from the main stage heater.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If heater density is increased on the stage to improve temperature uniformity, then temperature distribution is improved, but device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improvetemperature uniformity across substrateVSAvoidheater arrangement complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

Instead of increasing heater density uniformly across the stage, the system segments the heating function between two locations: the shaft (first heater) and the stage (second heater). This segmentation simplifies the stage heater design while achieving temperature uniformity through coordinated operation of both heaters, reducing manufacturing complexity compared to high-density stage-only heating.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The heating solution extends from a two-dimensional stage surface to a three-dimensional configuration by adding heating capability to the shaft structure. The first heater on the shaft provides thermal compensation in the vertical dimension, working synergistically with the second heater on the stage to achieve uniform temperature distribution without requiring excessive complexity in the stage heater arrangement.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Device complexity

If a single heater on the stage is used to reduce device complexity, then device complexity is reduced, but temperature uniformity deteriorates due to heat loss through the shaft

Engineering Contradiction:
Improveheater configuration simplicityVSAvoidtemperature uniformity
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The heating function is segmented into two simple, independent heater units located at different positions (shaft and stage), avoiding the need for a single complex high-power stage heater. This segmentation maintains relative device simplicity while effectively addressing temperature uniformity by compensating for shaft heat loss with the first heater.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first heater on the shaft serves as an intermediary heating element that prevents thermal energy from being lost through the shaft structure. This intermediary heater works in conjunction with the second stage heater to maintain temperature uniformity without requiring the stage heater to operate at excessively high power levels, thereby preserving temperature control effectiveness while keeping the overall system relatively simple.

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 configuration allows for precise and uniform temperature control of the substrate, reducing temperature variations and improving the consistency of thin film properties in semiconductor processes.

Implementation Method 1

a first heater (150) installed on the shaft (134) and a second heater (140) installed on the stage (132)

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

an electrostatic chuck for precise substrate fixation

Methodology Applied
Scientific EffectElectrostatic force: Electrostatics

Implementation Method 3

optional helium gas flow for enhanced thermal conductivity

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3591690B1Substrate supporting unit and film forming device having substrate supporting unit
Publication Date: 2022.10.05 NHK SPRING CO LTD
  • EP3591690B1 patent drawingFigure 1
  • EP3591690B1 patent drawingFigure 2A~2C
  • EP3591690B1 patent drawingFigure 3A~3B

AI summary

A substrate supporting unit is provided. The substrate supporting unit possesses a shaft, a first heater, and a stage. The first heater is located in the shaft and is configured to heat an upper portion of the shaft. The stage is located over the shaft and includes a first plate, a second plate over the first plate, and a second heater between the first plate and the second plate.