Electrostatic Chuck Heater High-Temperature Response
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Solution Overview
Problem
Conventional coulomb-type electrostatic chuck heaters experience degraded chucking and de-chucking response of substrates at high temperatures due to large crystal grain sizes in alumina sintered bodies, resulting from double sintering of dielectric and supporting layers, which lowers the volume resistivity of the dielectric layer.
Innovation Solution
The electrostatic chuck heater is manufactured with a base composed of an alumina sintered body, where the dielectric layer is formed by sintering alumina powder once, and the conductive material diffusion into the dielectric layer is controlled by applying a conductive paste with a binder, calcining, and then hot-press sintering, preventing the reduction in volume resistivity and maintaining high resistivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the dielectric layer is formed by sintering alumina sintered bodies twice (conventional method), then the manufacturing process is completed, but the crystal grain size becomes large and volume resistivity decreases, degrading chucking and de-chucking response at high temperature
Solution Approach 1:
The manufacturing process is segmented into two independent stages: first, forming the alumina sintered body with electrodes; second, forming the dielectric layer by sintering alumina powder separately. This segmentation prevents the dielectric layer from undergoing repeated sintering, maintaining small crystal grain size and high volume resistivity while still achieving complete manufacturing.
Solution Approach 2:
The electrodes are preliminarily formed on the alumina sintered body before the dielectric layer is formed. This preliminary action allows the dielectric layer to be formed separately by sintering alumina powder once, without requiring subsequent re-sintering of the entire structure, thus preventing crystal grain growth and maintaining high volume resistivity.
2Ease of manufacture
If conductive paste with binder is applied and sintered without calcining, then the electrostatic electrode is formed, but conductive material diffuses into the alumina powder, reducing volume resistivity
Solution Approach 1:
The alumina sintered body is preliminarily calcined before applying the conductive paste and forming the dielectric layer. This preliminary calcining removes the binder from the paste, preventing conductive material diffusion into the alumina powder during subsequent sintering, while still allowing the electrode formation process to proceed.
Solution Approach 2:
The binder removal step is skipped by performing preliminary calcining of the alumina sintered body before paste application. This rushes through the binder removal process beforehand, eliminating the need for prolonged high-temperature sintering that would cause conductive material diffusion, thus maintaining high volume resistivity.
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 approach improves the chucking and de-chucking response of substrates at high temperatures by maintaining high volume resistivity in the dielectric layer, ensuring better thermal uniformity and electrostatic attraction, and allowing for a thinner dielectric layer with reduced voltage requirements.
Implementation Method 1
an electrostatic field generating means for generating an electrostatic field
Implementation Method 2
a heater electrode which is embedded in lower part of the base and contains a conductive material
Implementation Method 3
hot-press sintering the stack of the alumina powder and the sintered body
Implementation Method 4
calcining the alumina sintered body
Data Source
AI summary
An electrostatic chuck heater is provided including a base which is formed by applying conductive paste containing a binder to upper and lower surfaces of an alumina sintered body to print an electrostatic electrode and heater electrode, calcining the alumina sintered body, arranging alumina powder above the electrostatic electrode and alumina powder below the heater electrode, and pressing the alumina powder and alumina sintered body in the above state for pressure sintering. The diffusion area ratio of the conductive material near the electrostatic electrode in the dielectric layer is set to not more than 0.25%.