Pulsed HF Power Signal Generation for Plasma Homogeneity
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Solution Overview
Problem
As plasma processes expand to larger areas, such as larger wafers in the semiconductor industry or larger flat-panel displays, achieving homogeneous plasma processing becomes difficult due to wave-like structures caused by the dimensions of the areas exceeding the wavelength of excitation signals, making it challenging to maintain uniformity in HF plasma processing.
Innovation Solution
A method and system that utilize at least two HF power generators, generating drive and pulse signals to produce pulsed HF power signals, allowing for flexible power supply to plasma chambers. This involves adjusting parameters like pulse frequency, duty cycle, and phase position of the signals to ensure optimal power distribution across electrodes, even when processing large areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple HF power generators are used to treat larger areas, then the processing area is increased, but wave-like structures appear in the plasma making homogeneous processing difficult
Solution Approach 1:
The patent applies periodic pulsed action by modulating the HF power generators with pulse signals having different duty cycles and pulse frequencies. This periodic modulation allows different regions of the plasma to be treated at different power levels and timing, counteracting the wave-like structures and achieving homogeneous plasma distribution across large processing areas
Solution Approach 2:
The patent changes multiple parameters including pulse frequency, duty cycle, and phase position of the drive signals for different HF power generators. By independently adjusting these parameters for each generator, the system optimizes power distribution across the plasma chamber to maintain homogeneity even when treating large areas with multiple generators operating at different frequencies
2Stability of the object's composition
If multiple HF power generators operate at different frequencies to counteract wave-like structures, then plasma homogeneity is improved, but system complexity increases
Solution Approach 1:
The patent employs a universal control architecture where a single control unit generates and coordinates drive signals and pulse signals for multiple HF power generators. This multi-functional control system can adjust frequency, phase, and duty cycle for all generators through a unified interface, reducing operational complexity despite the use of multiple generators with different frequencies
3Adaptability or versatility
If pulse signals with adjustable duty cycles and frequencies are used, then flexible power distribution is achieved, but signal generation complexity increases
Solution Approach 1:
The patent merges the functions of drive signal generation and pulse signal generation into an integrated control system. The control unit simultaneously generates HF drive signals and superimposes pulse modulation signals, combining multiple signal generation functions into a single coordinated system that reduces overall complexity while maintaining full flexibility in power distribution
Data Source
AI summary
For driving at least two HF power generators that supply a plasma process with HF power, at least one drive signal is generated and at least one pulse signal is generated. Then, based on the at least one drive signal and the at least one pulse signal, a pulsed HF power signal is generated by each of the at least two HF power generator.