Electrostatic Chuck Flame-Sprayed Insulating Film
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Solution Overview
Problem
Conventional electrostatic chucks face issues with plasma resistance, heat transfer, and reliability due to grain size and processing complexities, leading to early replacement and yield deterioration during waferless plasma cleaning.
Innovation Solution
An electrostatic chuck with a metal plate, a flame-sprayed insulating film, and a dielectric substrate with electrodes, bonded using an insulating adhesive, featuring a grain size of 2 μm or less for improved plasma resistance and heat transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If waferless plasma cleaning is performed to reduce tact time and improve production efficiency, then productivity is improved, but the average roughness increases due to grain release and boundary corrosion, deteriorating reliability
Solution Approach 1:
The patent changes the grain size parameter of the ceramic material from conventional 5-50 μm to 2 μm or less. This parameter change makes the material resistant to waferless plasma cleaning, allowing the electrostatic chuck to maintain its clamping force even after repeated plasma cleaning operations, thereby enabling continuous high-productivity operation without early replacement
Solution Approach 2:
The patent performs preliminary action by pre-reducing the grain size to 2 μm or less before the electrostatic chuck is put into service. This preliminary structural preparation ensures that the material can withstand subsequent waferless plasma cleaning operations without grain release or boundary corrosion, preventing the deterioration of clamping force before it occurs
2Ease of manufacture
If conventional hot pressing process is used to incorporate electrode inside dielectric layer, then manufacturing capability is achieved, but device complexity and processing time increase
Solution Approach 1:
The patent segments the manufacturing process into two independent stages: first forming the dielectric layer substrate with reduced grain size, then separately forming the electrode on its surface. This segmentation eliminates the need for complex hot pressing processes to embed electrodes within the dielectric layer during substrate formation, significantly reducing processing complexity and time
Solution Approach 2:
The patent performs preliminary action by first completing the dielectric layer substrate with optimized grain size structure, then subsequently forming the electrode on its surface. This preliminary formation of the substrate before electrode addition simplifies the overall manufacturing process compared to simultaneously embedding electrodes during substrate formation through hot pressing
3Reliability
If grain size is reduced to 2 μm or less to improve plasma resistance, then reliability is improved, but manufacturing difficulty increases due to binder removal issues during firing
Solution Approach 1:
The patent changes the grain size parameter to 2 μm or less and simultaneously optimizes the binder content and composition parameters. By controlling the binder to be 5-20 wt% of the total ceramic powder weight and using appropriate binder types, the patent enables successful firing at reduced grain sizes without excessive binder carbonization, resolving the manufacturing difficulty
Solution Approach 2:
The patent applies local quality by using different binder compositions or treatments in different regions or stages of the green sheet preparation and firing process. This allows for controlled binder removal and grain size reduction, achieving 2 μm or less grain size while preventing binder carbonization issues during firing
4Ease of manufacture
If insulating resin is used to bond dielectric layer to metal plate, then ease of manufacture is improved, but heat transfer coefficient deteriorates, increasing wafer temperature
Solution Approach 1:
The patent uses a composite material structure where the dielectric layer itself serves as the bonding interface between the metal plate and the wafer. By eliminating the insulating resin layer and directly bonding the dielectric layer to the metal plate, the patent creates a composite structure with superior thermal conductivity, reducing wafer temperature while maintaining electrical insulation through the dielectric layer
Solution Approach 2:
The patent extracts and removes the insulating resin layer from the bonding structure. By taking out the resin that causes poor heat transfer, the patent allows direct bonding of the dielectric layer to the metal plate, significantly improving the heat transfer path from wafer to cooling plate while the dielectric layer maintains necessary electrical insulation
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 enables reliable waferless plasma cleaning, maintains surface roughness, and enhances electrical insulation and heat transfer, reducing tact time and extending the chuck's lifespan.
Implementation Method 1
an insulating film which is formed on a surface of the metal plate by flame spraying
Data Source
AI summary
The object of the present invention is to provide an electrostatic chuck which has high plasma resistance and high capability of cooling a material to be clamped. As for the basic structure of the electrostatic chuck, an insulating film is formed on a surface of a metal plate by flame spraying, and a dielectric substrate is bonded onto the insulating film by an insulating adhesive layer. The top surface of the dielectric substrate is a surface for mounting a material to be clamped W such as a semiconductor wafer. Electrodes are formed on the lower surface of the dielectric substrate.