Plasma Processing Apparatus Abnormal Discharge Control
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Solution Overview
Problem
In plasma processing apparatuses, abnormal discharges such as arcing occur between substrates or ring assemblies and the mounting stage due to high gas pressure and moisture or impurities, leading to defects and inefficiencies in the plasma processing.
Innovation Solution
A plasma processing apparatus with a controller that adjusts the pressure of heat transfer gas and RF signal power to be lower than during normal plasma processing when mounting substrates or ring assemblies, and performs alternating gas supply and exhaust cycles to remove moisture and impurities before processing, thereby controlling abnormal discharges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high gas pressure is used during plasma processing, then plasma generation is improved, but abnormal discharge occurs between substrate/ring assembly and mounting stage
Solution Approach 1:
The patent applies preliminary action by performing gas supply and exhaust cycles before plasma processing to remove moisture and impurities from the mounting stage and substrate/ring assembly surfaces. This preliminary cleaning prevents abnormal discharge during subsequent high-pressure plasma processing, resolving the contradiction between maintaining high plasma stability and preventing abnormal discharge.
Solution Approach 2:
The patent implements periodic action through alternating gas supply and exhaust cycles that repeat multiple times before plasma processing. This periodic pumping and gas introduction removes accumulated moisture and impurities progressively, preventing abnormal discharge while allowing stable plasma processing to occur afterward.
2Productivity
If gas supply is increased to improve plasma processing, then processing efficiency is improved, but moisture and impurities cause abnormal discharge
Solution Approach 1:
The patent applies preliminary action by performing gas supply and exhaust cycles before plasma processing to remove moisture and impurities from the mounting stage and substrate/ring assembly surfaces. This preliminary cleaning prevents abnormal discharge during subsequent high-pressure plasma processing, resolving the contradiction between maintaining high plasma stability and preventing abnormal discharge.
Solution Approach 2:
The patent converts the harmful effect of gas pressure (which can cause abnormal discharge) into a beneficial cleaning mechanism. By using gas supply and exhaust cycles before processing, the same gas flow that could cause harm during plasma generation is instead used to remove moisture and impurities, transforming the harmful factor into a useful cleaning action.
3Productivity
If gas pressure is maintained high during mounting, then plasma processing is efficient, but abnormal discharge occurs due to high pressure
Solution Approach 1:
The patent applies preliminary action by performing gas supply and exhaust cycles before plasma processing to remove moisture and impurities from the mounting stage and substrate/ring assembly surfaces. This preliminary cleaning prevents abnormal discharge during subsequent high-pressure plasma processing, resolving the contradiction between maintaining high plasma stability and preventing abnormal discharge.
Solution Approach 2:
The patent applies dynamics by dynamically adjusting gas pressure conditions based on the processing stage. During mounting and preparation, gas is supplied and exhausted in cycles at controlled pressures. During actual plasma processing, high pressure is maintained. This dynamic adjustment of pressure conditions resolves the contradiction between efficiency and stability.
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 approach effectively reduces abnormal discharges, stabilizes the plasma processing environment, and ensures efficient removal of impurities and moisture, enhancing the reliability and efficiency of the plasma processing.
Implementation Method 1
a heat transfer gas supply supplying heat transfer gas between the mounting stage and at least one of the substrate and the ring assembly; a heat transfer gas exhauster exhausting the heat transfer gas from between the mounting stage and at least one of the substrate and the ring assembly
Implementation Method 2
an RF power supply supplying a radio frequency (RF) signal for plasma generation into the chamber
Data Source
AI summary
There is provided a plasma processing apparatus comprising: a chamber; a mounting stage mounting a substrate and a ring assembly on a periphery of the substrate; a fixation portion fixing at least one of the substrate and the ring assembly to the mounting stage; a heat transfer gas supply supplying heat transfer gas between the mounting stage and at least one of the substrate and the ring assembly; a heat transfer gas exhauster exhausting the heat transfer gas therefrom; an RF power supply supplying an RF signal for plasma generation; and a controller controlling the heat transfer gas supply so that pressure of the heat transfer gas is lower than that at the time of plasma processing for the substrate before performing the plasma processing for the substrate when at least one of the substrate and the ring assembly is mounted on the mounting stage.