Electrostatic Chuck Ceramic Substrate With Composite Oxide Bonding
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Solution Overview
Problem
Ceramic substrates used in electrostatic chucks for semiconductor manufacturing often have high temperature dependence of insulation resistance due to the presence of sintering agents, which can lead to decreased bonding strength with conductive materials like tungsten.
Innovation Solution
A ceramic substrate with a conductor layer and an electrostatic electrode, where the substrate main body comprises an insulator layer of high-purity aluminum oxide and a composite oxide layer of aluminum and silicon formed between the insulator layer and the conductor layer, using a conductive paste with tungsten, nickel oxide, and silicon dioxide, and firing without a sintering agent to improve sinterability and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a sintering agent (silica, magnesia, calcia, yttria) is included in alumina ceramics to enable co-firing with conductive paste, then bonding strength with tungsten conductor is improved, but insulation resistance decreases significantly at elevated temperatures
Solution Approach 1:
The patent removes sintering agents from the alumina ceramic composition to eliminate the source of insulation resistance degradation. By extracting the harmful component (sintering agent) while maintaining the co-firing capability through alternative mechanisms, the invention resolves the contradiction between bonding strength and insulation resistance.
Solution Approach 2:
The patent employs a composite oxide layer containing aluminum and silicon that forms during co-firing without requiring traditional sintering agents. This composite structure provides both the necessary bonding strength for tungsten attachment and maintains high insulation resistance at elevated temperatures, thus resolving the technical contradiction.
2Reliability
If alumina ceramics do not contain sintering agent to maintain high insulation resistance, then temperature dependence of insulation resistance is reduced, but bonding strength with tungsten conductor may not be obtained
Solution Approach 1:
The patent introduces a composite oxide layer of aluminum and silicon as an intermediary between the sintering-free alumina ceramic and the tungsten conductor. This intermediate layer facilitates strong bonding during co-firing while the underlying sintering-free alumina maintains high insulation resistance, thus resolving the contradiction.
Solution Approach 2:
The patent changes the chemical composition parameters of the conductive paste by adding aluminum oxide and silicon dioxide, which enable the formation of a bonding-promoting composite oxide layer during firing without requiring sintering agents in the ceramic body, thus maintaining both bonding strength and insulation resistance.
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 solution provides a ceramic substrate with high-purity aluminum oxide and improved adhesion between the conductor and substrate, maintaining insulation resistance characteristics at elevated temperatures without the need for sintering agents, enhancing the electrostatic chuck's performance.
Implementation Method 1
firing the green sheet and the conductor pattern to form the substrate main body and the electrostatic electrode
Data Source
AI summary
A ceramic substrate includes a substrate main body, and a conductor layer provided inside of the substrate main body. The substrate main body includes an insulator layer that is ceramics composed of aluminum oxide, and a composite oxide layer of aluminum and silicon, the composite oxide layer being formed between the insulator layer and the conductor layer.