Electrostatic Chuck Surface Structure for Particle Suppression
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Solution Overview
Problem
Existing electrostatic chuck devices face issues with particle generation and attachment to the rear surface of specimens during plasma etching, leading to insufficient cooling and potential damage from discharging.
Innovation Solution
The electrostatic chuck device features a ceramic plate-like body with multiple protrusions on one surface and fine protrusions or recesses on the other, optimizing the surface roughness and occupancy area to suppress particle generation and improve cooling efficiency, while a sheet-shaped insulating layer and organic adhesive layers enhance insulation and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If multiple protrusions are provided on the adsorption surface, then abnormal heat generation is suppressed, but particles are generated from coarse portions and attach to the rear surface of the specimen
Solution Approach 1:
The invention applies local quality by creating fine protrusions or recesses only in specific regions (coarse portions) of the adsorption surface, rather than uniformly across the entire surface. This localized modification suppresses particle generation at problematic areas while maintaining the heat dissipation function of the overall protrusion structure.
Solution Approach 2:
The adsorption surface is segmented into different functional zones: regions with multiple protrusions for heat management and regions with fine protrusions or recesses for particle suppression. This segmentation allows each zone to optimize its specific function without compromising the other.
2Object-generated harmful factors
If the adsorption surface is made coarse to suppress particle attachment, then particles are reduced, but cooling effect of cooling gas becomes insufficient
Solution Approach 1:
Instead of making the entire adsorption surface coarse, the invention applies surface roughness locally only to specific regions. The fine protrusions or recesses are concentrated in areas where particle attachment occurs, while other regions maintain smooth surfaces that facilitate cooling gas flow and heat dissipation.
3Ease of operation
If an electrostatic adsorption electrode is provided on the lower surface of a ceramic plate, then simple specimen fixation is achieved, but resistance to oxygen-based plasma and corrosive gas is weak
Solution Approach 1:
The invention uses a composite structure combining ceramic material (for plasma and corrosive gas resistance) with an electrostatic adsorption electrode (for specimen fixation). The electrostatic electrode is applied only to the lower surface of the ceramic plate, creating a composite system that leverages the strengths of both materials without compromising either function.
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 design effectively reduces particle attachment to the specimen's rear surface and enhances cooling performance, while also improving the insulating resistance and reducing the frequency of discharging-related breakages.
Implementation Method 1
an electrostatic adsorption electrode which generates an electrostatic force for holding the plate-like specimen on the placement surface
Implementation Method 2
the cooling effect of a cooling gas with respect to the incidence of plasma heat into the plate-like specimen, that is, the effect of conducting heat to the coarse adsorption surface
Data Source
AI summary
Provided is an electrostatic chuck device in which the attachment of particles to the rear surface of a plate-like specimen can be further suppressed by suppressing the generation source of the particles and, furthermore, an effect of cooling the plate-like specimen using a cooling gas can be improved. The electrostatic chuck device is formed by including an electrostatic chuck portion in which an upper surface (2a) of a ceramic plate-like body (2) is used as a placement surface on which a wafer is placed and an electrostatic adsorption electrode is provided inside the ceramic plate-like body (2) or on the rear surface thereof, multiple protrusions (11) are formed on the upper surface (2a), and multiple fine protrusions (13) are formed in regions (12) excluding the multiple protrusions (11) in the upper surface (2a).