Labyrinth Electrostatic Chuck for Lightup Prevention
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Solution Overview
Problem
Existing electrostatic chucks in semiconductor processing facilities face issues with lightup and arcing due to low-pressure gases and electric voltage gradients, which current solutions like dielectric coatings and porous plugs are inadequate in preventing, especially due to manufacturing complexities and potential gaps.
Innovation Solution
A labyrinthine ceramic structure with multiple layers and cutouts is used in the electrostatic chuck, forming a maze-like gas path that minimizes straight-line particle acceleration, combined with a porous ceramic plug and electrically insulating coatings to prevent lightup, which is easier to manufacture and align.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single channel through a top dielectric layer is used, then the structure is simple, but lightup may occur because the layer may be thick enough to cause arcing
Solution Approach 1:
The top dielectric layer is segmented into multiple thinner layers (first dielectric layer and second dielectric layer) separated by an intermediate layer. This segmentation reduces the thickness of each individual dielectric layer, preventing lightup while maintaining the overall structural integrity and gas distribution function.
2Reliability
If a porous plug of dielectric material is used in the top layer, then lightup is prevented by creating a tortuous gas path, but manufacturing and alignment become difficult and complicated
Solution Approach 1:
Instead of using a single porous plug, the invention segments the dielectric structure into multiple layers with defined interfaces. The gas distribution channels are formed as discrete features in each layer, which are easier to manufacture and align than a monolithic porous plug structure.
Solution Approach 2:
An intermediate layer is introduced between the first and second dielectric layers to facilitate manufacturing and alignment. This intermediate layer acts as a mediator that simplifies the assembly process and ensures proper positioning of the gas distribution channels across layers.
3Reliability
If dielectric coating is applied inside holes, then lightup is prevented, but the path length of gas molecules within the holes is not reduced
Solution Approach 1:
The gas distribution system is segmented into multiple layers with intermediate channels. This segmentation creates multiple shorter gas paths through the dielectric structure, reducing the overall path length that gas molecules must travel compared to a single long channel, while still preventing lightup through the layered dielectric configuration.
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 effectively reduces lightup and arcing by forcing gas molecules to take a tortuous path, eliminating long open spaces and simplifying the manufacturing process, while ensuring secure alignment and reduced risk of gaps.
Implementation Method 1
a porous plug of dielectric material in the top layer of the electrostatic chuck, so that gas takes a tortuous path through the hole in the electrostatic chuck
Implementation Method 2
the insert may be coated on one or more sides with an electrically insulating material
Implementation Method 3
joining the ceramic layers, such that the ceramic layers form the wafer ceramic, for example by co-sintering
Data Source
AI summary
In accordance with this disclosure, there are provided several inventions, including an electrostatic chuck apparatus comprising multiple layers with cutouts that form a labyrinth structure which defined a path for cooling or heating gas. The structure prevents particles from accelerating such that they form unwanted lightup in the gas flow path.