Electrostatic Chuck Aperture-Reducing Plug for High Power Plasma
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Solution Overview
Problem
Current electrostatic chucks (ESC) designs fail to withstand high power and high bias voltages, leading to issues such as bond failures, plasma ignition in gas holes, and increased difficulty in wafer de-chucking due to temperature fluctuations and charge buildup during high aspect ratio plasma etching processes.
Innovation Solution
The ESC incorporates a porous plug in the cooling plate to prevent plasma light-up in helium holes, which delivers helium for backside wafer cooling, reducing arcing and temperature differences by pumping helium through a central gas hole and peripheral holes, and using a dielectric coating to reduce electrical conductivity and prevent arcing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high power plasma processing is applied to achieve high aspect ratio etching, then etching performance is improved, but ESC reliability deteriorates due to dielectric breakdown and plasma ignition in gas holes
Solution Approach 1:
A dielectric coating layer is applied to the inner surface of gas holes to act as an intermediary barrier. This coating prevents direct plasma contact with the gas hole walls, eliminating plasma ignition while maintaining gas flow functionality. The dielectric material serves as a mediator between the plasma environment and the ESC structure, protecting against dielectric breakdown at high power levels.
Solution Approach 2:
The physical and chemical parameters of the gas hole surface are changed by applying a dielectric coating. This modifies the surface properties to prevent plasma formation and reduce electrical conductivity, allowing the ESC to withstand high power plasma processing conditions without breakdown while maintaining operational reliability.
2Manufacturing precision
If high bias power is increased to achieve bending free profiles in HAR etching, then etching quality is improved, but bond strength deteriorates due to radical erosion
Solution Approach 1:
The dielectric coating in the gas holes acts as a barrier that reduces radical erosion pathways. By preventing plasma ignition and controlling gas flow through the coated surfaces, the coating protects bond interfaces from direct radical attack, maintaining bond strength even under high bias power conditions required for bending-free profile etching.
3Productivity
If RF plasma power is increased to improve deposition rate, then productivity is improved, but temperature control deteriorates due to increased heating
Solution Approach 1:
The dielectric coating changes the thermal and electrical parameters of the gas hole surfaces. This modification affects heat distribution and plasma coupling, allowing better temperature management during high power plasma processing while maintaining improved deposition rates.
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 arcing and bond failures, enhances cooling efficiency, and improves wafer de-chucking by maintaining stable temperature and reducing radical erosion, allowing the ESC to handle high power plasma processing without breakdown.
Implementation Method 1
using a dielectric coating to reduce electrical conductivity and prevent arcing
Implementation Method 2
delivers helium for backside wafer cooling
Implementation Method 3
enhances cooling efficiency
Data Source
AI summary
An electrostatic chuck is described to carry a workpiece for processing such as high power plasma processing. In embodiments, the chuck includes a top plate to carry the workpiece, the top plate having an electrode to grip the workpiece, a cooling plate under the top plate to cool the top plate, a gas hole through the cooling plate and the top plate to feed a gas to the workpiece through the top plate, and an aperture-reducing plug in the cooling plate gas hole to conduct gas flow through the hole.