Plasma Processing Stage Liner for Through-Hole Discharge Suppression
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Solution Overview
Problem
Plasma processing stages with through-holes experience abnormal discharge due to high RF power applications, leading to potential damage and reduced yield, especially when heat transfer gases flow through ceramic insulators with high permittivity, causing electric charge buildup and potential differences.
Innovation Solution
Incorporating cylindrical liners with a relative permittivity of 5 or less, such as fluorine-containing materials like PFA or PTFE, within the through-holes to reduce the potential difference and prevent electron avalanches, thereby minimizing abnormal discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ceramic insulators with high permittivity are used in through-holes for heat transfer gas, then insulation performance is improved, but abnormal discharge occurs due to electric charge buildup
Solution Approach 1:
The patent changes the key parameter of permittivity from high (ceramic materials with permittivity > 10) to low (materials with permittivity ≤ 5). This parameter change fundamentally alters the electrical behavior in the through-hole, preventing charge buildup that leads to abnormal discharge while maintaining the necessary insulation function.
Solution Approach 2:
The patent introduces a liner as an intermediary component within the through-hole. This liner acts as a mediator between the heat transfer gas and the chamber wall, providing a surface with low permittivity that prevents electron avalanche and abnormal discharge while still allowing thermal conduction for substrate cooling.
2Productivity
If RF power is increased for plasma processing, then processing efficiency is improved, but abnormal discharge increases causing damage
Solution Approach 1:
The patent applies preliminary anti-action by pre-installing the low permittivity liner in the through-hole before plasma processing begins. This preventive measure counteracts the potential for abnormal discharge before it can occur, allowing high RF power to be applied safely without the harmful effects of electron avalanche and abnormal discharge.
3Temperature
If through-holes are used for heat transfer gas, then substrate cooling is improved, but electric charge buildup occurs in high permittivity materials
Solution Approach 1:
The patent applies local quality by modifying only the specific region where the problem occurs - the inner surface of the through-hole - while leaving the rest of the substrate cooling system unchanged. The low permittivity liner is applied locally to the through-hole wall, providing the necessary electrical properties without affecting the overall thermal conduction path for substrate cooling.
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 use of low permittivity liners effectively prevents abnormal discharge, increasing the withstand voltage and maintaining substrate and edge ring cooling efficiency while reducing the risk of electric damage and heat production.
Implementation Method 1
a first cylindrical liner disposed in the second hole, the first cylindrical liner having a relative permittivity of 5 or less
Implementation Method 2
reduce the potential difference and prevent electron avalanches, thereby minimizing abnormal discharge
Implementation Method 3
a heat transfer gas flows through the through-hole and is supplied to a portion between a lower surface of the substrate and the mounting surface of the stage
Data Source
AI summary
A stage to be disposed in a chamber of a plasma processing apparatus is provided. The stage includes a chuck with a mounting portion for a substrate and a first hole through the mounting portion. The stage includes a base disposed beneath the chuck, the base including a second hole through the base, and the second hole communicating with the first hole. The base includes a first cylindrical liner disposed in the second hole, the first cylindrical liner having a relative permittivity of 5 or less.