Multi-Plate Stage Layout for Large Wafer Temperature Gradients

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Solution Overview

Problem

Conventional ceramic stages used in semiconductor manufacturing face limitations in achieving a temperature gradient profile with a temperature difference greater than 10°C between the inner and outer regions, leading to potential damage and deformation due to thermal stress.

Innovation Solution

A stage design utilizing a metal plate structure with integrated circulating flow paths and heaters, separated by a heat insulating portion, allowing for a large temperature difference between inner and outer regions while minimizing thermal stress through a heat insulating portion that acts as a thermal choke.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a ceramic stage is used to achieve heat resistance and contamination resistance, then reliability is improved, but the temperature gradient capability is limited to about 10°C due to thermal stress damage and deformation

Engineering Contradiction:

Improveheat resistance and contamination resistanceVSAvoidtemperature gradient capability

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The stage is divided into multiple metal plates (first metal plate, second metal plate, third metal plate) stacked in the thickness direction, with heat insulating portions inserted between them. This segmentation allows independent temperature control of inner and outer regions while maintaining structural integrity and resistance to thermal stress.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The stage combines metal plates (for thermal conductivity and structural strength) with heat insulating portions (for thermal isolation). This composite structure enables large temperature gradients (20°C or more) between inner and outer regions while preventing thermal stress damage, overcoming the limitations of pure ceramic stages.

Inventive Principle:

Principle #40Composite materials

2Temperature

If the temperature difference between inner and outer regions is increased beyond 10°C in a ceramic stage, then temperature gradient capability is improved, but thermal stress causes damage and deformation

Engineering Contradiction:

Improvetemperature difference between inner and outer regionsVSAvoidresistance to thermal stress damage

Core Design Contradiction:

TemperatureVSStrength

Solution Approach 1:

Heat insulating portions are inserted between metal plates at the inner peripheral region to act as thermal intermediaries. These insulating portions block heat flow between inner and outer regions, enabling large temperature differences (20°C or more) without causing thermal stress damage or deformation to the stage structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Temperature

If a heat insulating portion is inserted between metal plates at the inner peripheral region, then temperature gradient capability is improved to 20°C or more, but device complexity increases

Engineering Contradiction:

Improvetemperature gradient profileVSAvoidstructure complexity with multiple plates and insulating portions

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The heat insulating portions are nested between the stacked metal plates in the thickness direction, with the first heat insulating portion between the first and second metal plates, and the second heat insulating portion between the second and third metal plates. This nested arrangement achieves complex thermal control functionality while maintaining a compact overall structure.

Inventive Principle:

Principle #7Nested doll (Nesting)

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 stage achieves a temperature gradient profile with a temperature difference of at least 20°C, effectively correcting significant temperature drops in semiconductor wafers, enhancing temperature uniformity and reducing deformation due to thermal expansion.

Implementation Method 1

a heat insulating portion in which the first groove, the first through hole, and at least one of the second groove and the second through hole are connected to one another

Methodology Applied

Scientific EffectThermal Insulation: Thermal Insulation

Implementation Method 2

a first circulating flow path and a first heater provided in one of the first metal plate, the second metal plate, and the third metal plate, and one of a second circulating flow path and a second heater

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 3

a first heater and the second heater are provided in a second region opposite the first region defined by the heat insulating portion as the boundary

Methodology Applied

Scientific EffectJoule Heating: Joule Heating

Data Source

PatentUS20250246454A1stage

Publication Date: 2025.07.31 NHK SPRING CO LTD

AI summary

A stage includes a first metal plate including a first groove, a second metal plate including a through hole below the first metal plate, a third metal plate including a second groove below the second metal plate, a heat insulating portion in which the first groove, the through hole, and the second groove are connected to one another, a first circulating flow path and a first heater provided in one of the first metal plate, the second metal plate, and the third metal plate, and one of a second circulating flow path and a second heater. The first circulating flow path and the second circulating flow path are provided in a first region defined by the heat insulating portion as a boundary. The first heater and the second heater are provided in a second region opposite the first region defined by the heat insulating portion as the boundary.