Aluminum Nitride Sample Holder with Low Oxygen Region
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Solution Overview
Problem
The electrostatic chuck used in film forming apparatuses for semiconductor manufacturing experiences degraded thermal uniformity due to heat generation by the electrode, which increases the dielectric tangent of the ceramic substrate, leading to potential reactions with oxygen and instability under plasma conditions.
Innovation Solution
A sample holder with a ceramic substrate primarily composed of aluminum nitride, featuring a low oxygen region around the electrical conductor to minimize dielectric tangent increase and heat generation, and an electrostatic adsorbing electrode to maintain uniformity and stability during high-frequency operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a high frequency alternating current is allowed to pass through the electrode, then the electrode generates heat for film formation, but the dielectric tangent of the ceramic substrate increases and thermal uniformity degrades
Solution Approach 1:
The patent applies local quality by creating a low oxygen content region specifically around the electrical conductor within the ceramic substrate. This localized modification of material composition (reducing oxygen content from typical ceramic levels to less than 1 wt%) addresses the heat generation issue at the electrode interface without compromising the overall structural integrity of the substrate. The selective oxygen reduction in the vicinity of the conductor allows controlled dielectric tangent and thermal properties where needed while maintaining standard ceramic properties in other regions.
2Reliability
If the oxygen content in the ceramic substrate is reduced around the electrical conductor, then the dielectric tangent increase is suppressed, but the manufacturing complexity increases
Solution Approach 1:
The patent implements parameter changes by modifying the oxygen content parameter in the ceramic substrate from typical levels (several wt%) to a reduced level (less than 1 wt%) in the region surrounding the electrical conductor. This parameter modification directly addresses the dielectric tangent stability issue. The patent specifies that the low oxygen content region should extend to within 1 mm from the electrical conductor, providing a quantitative parameter change that balances performance improvement with manufacturing feasibility.
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 ensures improved thermal uniformity and reduced heat generation, maintaining stable plasma conditions and enhancing the reliability and uniformity of film formation processes.
Implementation Method 1
when a high frequency alternating current is allowed to pass through the electrode, since the electrode generates heat
Implementation Method 2
the dielectric tangent may be partially increased in the ceramic substrate. As a result, the thermal uniformity of the main surface of the ceramic substrate may be degraded
Implementation Method 3
an electrostatic chuck disclosed in Japanese Unexamined Patent Application Publication No. 7-130826... includes a ceramic substrate and an electrode provided therein. This electrostatic chuck mounts an object to be heated on a main surface of the ceramic substrate
Data Source
AI summary
A sample holder includes a substrate which is formed of a ceramic containing aluminum nitride as a primary component and which has an outer surface functioning as a sample holding surface and an electrical conductor which is provided in the substrate and which faces the sample holding surface. In this sample holder, at the sample holding surface side in the substrate than the electrical conductor, the oxygen content of the ceramic is small in a region located inside the periphery of the electrical conductor as compared to that in a region located outside the periphery thereof.