Electrostatic Chuck Step-Groove Structure to Block Adhesive Smudging
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Solution Overview
Problem
The existing substrate fixing devices with electrostatic chucks face issues where silicone adhesive seeps between ceramic substrates, causing smudges on the adsorption surface, which can transfer to wafers and impair the uniform temperature distribution, leading to heat-equalizing performance issues.
Innovation Solution
The electrostatic chuck is designed with ceramic substrates having steps at their peripheral edges, arranged to face each other, and a filling portion, such as a sprayed alumina or yttria, is used to fill the groove formed by these steps, preventing adhesive components from seeping to the adsorption surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If multiple ceramic substrates are bonded to the base plate using silicone adhesive, then the electrostatic chuck can be constructed to adsorb large-scale wafers, but the adhesive components seep to the adsorption surface causing smudges that deface the wafer
Solution Approach 1:
The electrostatic chuck is segmented into multiple ceramic substrates (typically four 250mm×250mm substrates arranged to form a 500mm×500mm adsorption area). Each substrate is bonded to the base plate with silicone adhesive, enabling large-scale wafer adsorption while managing the complexity of large area bonding through modular construction
Solution Approach 2:
A barrier layer (such as alumina or yttria coating) is introduced as an intermediary between the silicone adhesive and the ceramic substrate adsorption surface. This barrier layer prevents the adhesive components from seeping through to the adsorption surface, thereby blocking the harmful effect while maintaining the bonding function
2Area of stationary object
If ceramic substrates are arranged adjacent to each other without spacing, then the adsorption surface area is maximized, but the adhesive introduces contamination to the adsorption surface
Solution Approach 1:
A barrier coating (alumina, yttria, or other ceramic materials) is applied as an intermediary layer on the adsorption surface of each ceramic substrate. This intermediary layer prevents adhesive components from migrating to the adsorption surface even when substrates are arranged adjacent without spacing, thus maintaining both maximum adsorption area and surface cleanliness
Solution Approach 2:
A thin film barrier layer is deposited on the ceramic substrate surfaces to provide contamination protection. This thin film acts as a flexible barrier that prevents adhesive seepage while maintaining the structural integrity and thermal properties of the ceramic substrates
3Object-affected harmful factors
If ceramic substrates are spaced apart on the base plate, then adhesive contamination is prevented, but the temperature distribution on the adsorption surface becomes non-uniform
Solution Approach 1:
A barrier layer (alumina, yttria, or other ceramic coating) is introduced as an intermediary that allows thermal conduction while blocking adhesive contamination. This enables the ceramic substrates to be arranged adjacent without spacing (maintaining temperature uniformity) while the barrier layer prevents adhesive components from reaching the adsorption surface
Solution Approach 2:
The ceramic substrate is combined with a barrier coating layer to form a composite structure. The ceramic substrate provides mechanical strength and thermal conductivity for temperature uniformity, while the barrier coating layer (such as alumina or yttria) provides contamination resistance, achieving both thermal performance and surface cleanliness
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 configuration prevents smudges on the adsorption surface, maintaining the heat-equalizing performance by ensuring uniform temperature distribution across the adsorption surface.
Implementation Method 1
a filling portion that fills a groove portion formed by the facing steps of the adjacent ceramic substrates
Implementation Method 2
The substrate fixing device can adsorb the wafer to the electrostatic chuck by applying a voltage to the electrode embedded in the ceramic substrate of the electrostatic chuck and using an electrostatic force generated according to the voltage
Implementation Method 3
a flexible silicone-based adhesive is used so as to favorably maintain thermal conductivity and to absorb a difference of thermal expansions between the base plate and the electrostatic chuck
Implementation Method 4
a flexible silicone-based adhesive is used so as to favorably maintain thermal conductivity and to absorb a difference of thermal expansions between the base plate and the electrostatic chuck
Data Source
AI summary
An electrostatic chuck includes a plurality of ceramic substrates each having a step formed at a peripheral edge portion of one surface, the ceramic substrates being arranged adjacent to each other so that the steps face each other, electrodes each embedded in each of the plurality of ceramic substrates, and a filling portion that fills a groove portion formed by the facing steps of the adjacent ceramic substrates.