Plasma Processing Device Independent Ion Radical Control
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Solution Overview
Problem
Conventional plasma processing apparatuses face difficulties in independently controlling the densities of ions and radicals in plasma, which hinders the achievement of required processing characteristics such as Critical Dimension (CD) or mask selectivity on semiconductor surfaces due to the lack of a potential difference between the plasma generation space and the processing space.
Innovation Solution
A plasma processing apparatus with a dielectric member and electrodes that allows for independent control of radical and ion densities by adjusting the total power and power ratio supplied to the electrodes, creating a potential difference to form sheaths and control the plasma composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a grid electrode with multiple through holes is used to divide the processing vessel into two spaces, then plasma can be generated in a plasma generation space and introduced into a processing space, but it becomes difficult to independently control the densities of ions and radicals in the plasma
Solution Approach 1:
The plasma generation space and processing space are physically segmented by a dielectric member with communication holes, allowing independent plasma generation and processing. The power splitter further segments the power supply control, enabling separate control of plasma generation power and bias power, which independently controls radical and ion densities respectively.
Solution Approach 2:
The dielectric member acts as an intermediary between the plasma generation space and processing space, allowing plasma to pass through while maintaining potential difference. The power splitter serves as an intermediary in the power supply system, distributing power to different electrodes independently to control plasma parameters.
2Productivity
If the processing space is depressurized to introduce processing gas and radicals from the plasma generation space, then plasma process can be performed on the processing target object, but the plasmas have the same potential making independent control difficult
Solution Approach 1:
The invention intentionally breaks equipotentiality between the plasma generation space and processing space by applying different powers to the electrodes. The plasma generation electrodes and mounting table are maintained at different potentials, creating a sheath that enables independent control of ion and radical densities while maintaining high processing rate.
3Quantity of substance
If high frequency power is supplied to generate plasma in the plasma generation space, then radicals are produced for the plasma process, but ion density cannot be independently controlled
Solution Approach 1:
High frequency power is supplied periodically to the plasma generation electrodes to generate plasma and radicals. The periodic nature of high frequency power supply allows continuous plasma generation while the separate bias power control on the mounting table independently manages ion acceleration and density.
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
Enables independent control of ion and radical densities within the processing space, allowing for precise adjustment of processing characteristics like CD and mask selectivity, enhancing the plasma processing rate and uniformity.
Implementation Method 1
a first high frequency power supply configured to supply a first high frequency power to the first electrode and the second electrode to generate a first plasma of the first processing gas supplied into the internal space
Implementation Method 2
a second high frequency power supply configured to supply a second high frequency power to the mounting table to generate a second plasma of the first processing gas introduced into the processing space and to attract ions in the second plasma into the processing target object
Implementation Method 3
a depressurizing device configured to depressurize the processing space to introduce the first processing gas and radicals in the first plasma into the processing space from the internal space through the communication holes
Data Source
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AI summary
A plasma processing apparatus includes a dielectric member having communication holes through which an internal space communicates with a processing space; a first electrode and a second electrode arranged to face each other with the internal space therebetween; a first gas supply device which supplies a first processing gas into the internal space; a first high frequency power supply which supplies a first high frequency power to at least one of the first electrode and the second electrode to generate a first plasma of the first processing gas; a depressurizing device which introduces the first processing gas and radicals in the first plasma into the processing space; a second high frequency power supply which supplies a second high frequency power to generate a second plasma of the first processing gas and to attract ions into a target object; and a control unit which adjusts, by controlling a total amount of the first high frequency powers, an amount of the radicals in the second plasma and adjusts, by controlling a ratio between the first high frequency powers, an amount of the ions in the second plasma.