Substrate Heater Connector Material to Suppress Ceramic Cracks

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Solution Overview

Problem

The existing substrate heating devices face issues with thermal stress and compressive stress due to the difference in coefficient of thermal expansion between ceramic and metal materials during the sintering process, leading to crack generation and reduced durability and lifespan.

Innovation Solution

A substrate heating device with a body made of aluminum nitride and using a molybdenum-tungsten alloy for the connector connecting element, which reduces thermal stress and compressive stress by matching the coefficient of thermal expansion, and a power transfer wire with a larger diameter to minimize heat generation and overheating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a metal wire is used to connect the heater connector in the ceramic substrate heating device, then electrical conductivity is achieved, but thermal stress and compressive stress occur due to coefficient of thermal expansion difference between ceramic and metal, causing crack generation

Engineering Contradiction:

Improvedurability of substrate heating deviceVSAvoidthermal stress and compressive stress

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the material parameter (coefficient of thermal expansion) by selecting a molybdenum-tungsten alloy whose CTE matches that of aluminum nitride ceramic. This parameter matching eliminates thermal stress and compressive stress during high-temperature sintering processes, preventing crack generation and improving device reliability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite molybdenum-tungsten alloy material that combines the properties of both metals to achieve a coefficient of thermal expansion matching the ceramic body. This composite material approach allows simultaneous electrical conductivity and thermal stress compatibility

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If high pressure is applied during the sintering process to manufacture the ceramic body, then sintering is completed, but compressive stress is induced causing cracks in the ceramic

Engineering Contradiction:

Improvesintering process completionVSAvoidcrack resistance of ceramic body

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The patent applies beforehand cushioning by pre-matching the coefficient of thermal expansion between the connector material and ceramic body. This preparatory measure cushions against the compressive stress that will be induced during high-pressure sintering, preventing crack generation while allowing the sintering process to complete successfully

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Temperature

If the same amount of heat is applied to each area of the substrate heating device, then heating uniformity is attempted, but temperature deviation occurs between inner area and outer area

Engineering Contradiction:

Improvetemperature uniformity across substrateVSAvoidtemperature control precision

Core Design Contradiction:

TemperatureVSManufacturing precision

Solution Approach 1:

The patent applies local quality by positioning a supporting element with increased heat capacity specifically in the center area of the substrate heating device. This localized modification compensates for the lower heat capacity in outer areas, achieving temperature uniformity across the entire substrate surface

Inventive Principle:

Principle #3Local quality

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

Effectively suppresses crack formation, enhances thermal uniformity, and extends the lifespan of the substrate heating device by reducing thermal and compressive stresses during high-temperature and high-pressure processes.

Implementation Method 1

the difference in coefficient of thermal expansion (CTE) between the ceramic that constitutes the body and the metal material of the wire induces thermal stress

Methodology Applied

Scientific EffectCoefficient of thermal expansion matching: Thermal Expansion

Implementation Method 2

a heater is contained, thereby increasing the heat capacity

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS20240063033A1Substrate heating device configured to suppress crack generation

Publication Date: 2024.02.22 MICOCERAMICS LTD

AI summary

The present disclosure relates to a substrate heating device capable of effectively suppressing the generation of cracks. The substrate heating device including: a body having a substrate seating element on which a substrate is seated, thereby supporting the substrate; a first heating element positioned in an inner area of the body; a second heating element positioned in an outer area surrounding the inner area of the body; a power transfer wire configured to transfer a current to the second heating element across the inner area of the body; a heater connector configured to supply a current to the power transfer wire; and a connector connecting element connected from the heater connector to the power transfer wire, wherein the connector connecting element is made of molybdenum-tungsten alloy including molybdenum and tungsten.