Ceramic-Coated High-Frequency Electrode for Plasma Processing
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Solution Overview
Problem
Plasma processing apparatuses face challenges in preventing heavy-metal contamination and corrosion of high-frequency electrodes due to thermal contraction and ion sputtering, especially during long-term use, which affects semiconductor device manufacturing by introducing defects and particles.
Innovation Solution
The apparatus employs a ceramic or dielectric-coated gas shower plate with a high-frequency electrode, using materials like quartz or ceramic compositions (e.g., Al2O3, SiC, Y2O3) to reduce corrosion and heavy-metal contamination, and incorporates a polymer sealing treatment to enhance durability and prevent ion sputtering damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If alumite-treated aluminum or stainless steel is used as the base material for the high-frequency electrode and processing chamber, then resistance to process gases is improved, but thermal contraction causes alumite coating to crack and remove during long-term continuous operation
Solution Approach 1:
The patent uses a composite structure consisting of an aluminum base material with an alumite coating layer. This composite material combines the high corrosion resistance of alumite with the thermal properties of aluminum, resolving the contradiction between gas resistance and thermal stability by creating a multi-layer protective system.
2Manufacturing precision
If a thick ceramic sprayed film is used to reduce heavy-metal contamination, then purity is improved, but the film is susceptible to ion sputtering and has short lifespan
Solution Approach 1:
The patent applies ceramic spraying selectively to specific areas of the high-frequency electrode that are most exposed to plasma and ion bombardment. By concentrating the protective coating where it is most needed rather than applying it uniformly throughout, the film's protective function is maximized while its lifespan is extended through localized reinforcement.
Solution Approach 2:
The ceramic sprayed film is applied in advance to the high-frequency electrode surface before plasma processing begins. This preliminary protective layer prevents direct contact between ions and the base material, reducing sputtering damage and extending the electrode's operational life before maintenance is required.
3Productivity
If high-frequency power is applied to generate plasma, then plasma generation efficiency is improved, but ion sputtering and reactive radical corrosion damage the electrode surface
Solution Approach 1:
The patent introduces a ceramic sprayed film as an intermediary layer between the high-frequency electrode and the plasma environment. This intermediate coating absorbs the impact of ion sputtering and reactive radical corrosion, protecting the underlying aluminum base material while allowing plasma generation to proceed efficiently at high power levels.
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 effectively reduces heavy-metal contamination and extends the lifespan of the high-frequency electrode by preventing corrosion and ion sputtering, ensuring stable and uniform plasma generation and processing performance.
Implementation Method 1
a high-frequency electrode (antenna electrode) for supplying high-frequency radiation for discharging the gas and forming plasma
Implementation Method 2
the surface of the high-frequency electrode 120, especially the surface of the gas shower plate 106, and the inner surface of the processing chamber 101 coming into contact with plasma 102 are subjected to sputtering by ions irradiated from plasma
Implementation Method 3
incorporates a polymer sealing treatment to enhance durability and prevent ion sputtering damage
Data Source
AI summary
The invention provides a plasma processing apparatus aimed at suppressing the corrosion caused by reactive gas and heavy-metal contamination caused by plasma damage of components constituting the high-frequency electrode and gas supply unit. The plasma processing apparatus comprises a processing chamber 1 for subjecting a processing substrate 4 to plasma processing, gas supply means 17, 16 and 11 for feeding gas to the processing chamber 1, and an antenna electrode 10 for supplying high-frequency radiation for discharging the gas to generate plasma, wherein the gas supply means includes a gas shower plate 11 having gas discharge holes on the surface exposed to plasma, and a portion of or a whole surface of the conductor 10 exposed to gas constituting the antenna-electrode side of the gas supply means is subjected to ceramic spraying containing no heavy metal to form a protecting film 12.