Electrostatic Chuck Through-Hole Layout to Prevent Plasma Breakdown
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Solution Overview
Problem
Existing electrostatic chucks face challenges in preventing dielectric breakdown during the use of plasma in semiconductor manufacturing processes, particularly due to the proximity of electrostatic attraction electrodes and through-holes, which can lead to plasma discharge and short-circuits.
Innovation Solution
The electrostatic chuck design incorporates a ceramic substrate with through-holes and a porous member, where the second through-hole has a larger diameter opening than the first, and the electrodes are positioned to maintain a clearance, reducing the likelihood of dielectric breakdown by keeping the porous members away from the electrodes, and using a sleeve and recess structures to further prevent plasma contact with the support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If through-holes are provided in the substrate for gas flow, then gas circulation is improved, but dielectric breakdown risk increases due to proximity of electrodes and through-holes
Solution Approach 1:
A porous member is introduced as an intermediary component between the through-hole and the electrostatic attraction electrode. This porous member prevents direct contact between plasma and the electrode while still allowing gas to pass through, thereby maintaining gas flow efficiency while preventing dielectric breakdown.
Solution Approach 2:
The patent applies different structural characteristics to different regions: the porous member has a specific porosity (30-70%) that allows gas permeation while providing electrical insulation. The opening diameter of the second through-hole is specifically designed to be larger than the first through-hole to maintain gas flow while increasing distance from the electrode.
2Reliability
If porous members are placed in through-holes to prevent plasma contact, then dielectric breakdown is reduced, but gas flow resistance increases
Solution Approach 1:
The patent utilizes porous members with controlled porosity (30-70%) made of materials such as alumina, aluminum nitride, or silicon nitride. These porous materials provide both electrical insulation to prevent plasma discharge and sufficient gas permeability to maintain efficient gas flow through the electrostatic chuck.
3Reliability
If the opening of the second through-hole is made larger, then distance from electrode increases reducing breakdown risk, but structural complexity increases
Solution Approach 1:
The through-hole structure is segmented into two parts: a first through-hole in the substrate and a second through-hole in the support. The second through-hole has a larger opening diameter than the first, creating a stepped configuration that increases clearance from the electrode while maintaining manufacturing feasibility through standard drilling and machining operations.
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 the risk of dielectric breakdown, allowing for stable plasma generation and efficient gas flow while maintaining electrostatic attraction, enhancing the reliability and performance of the electrostatic chuck in semiconductor processing.
Implementation Method 1
an electrode for electrostatic attraction located inside the substrate
Implementation Method 2
a porous member located in the second through-hole and fixed to the second main surface
Data Source
AI summary
An insulating substrate has a sample holding surface. A support is bonded to the insulating substrate. A first through-hole in the insulating substrate and a second through-hole in the support are continuous with each other to serve as a gas inlet. A porous member is located in the second through-hole. The second through-hole has, at its opening adjacent to the insulating substrate (opening adjacent to the substrate), a larger diameter than the first through-hole. The opening of the second through-hole and an electrostatic attraction electrode are at different positions in a direction parallel to the sample holding surface. The electrostatic attraction electrode and the second through-hole avoid overlapping each other as viewed from above.