DC-to-DC Converter for Plasma Etching
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Solution Overview
Problem
Current plasma processing systems face complexity and cost challenges due to the need for precise control of RF power pulsing sequences, timing, and impedance matching, which are not efficiently addressed by traditional RF generators.
Innovation Solution
A direct current (DC) to DC converter system that independently controls positive and negative pulses in voltage amplitude, polarity, rise and decay times, and delay, converting DC voltage to RF and back to DC through a resonant circuit and diode network, allowing for rapid pulsing without impedance complications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional RF generators are used to supply power to plasma processing systems, then the plasma etching process can be performed, but the system complexity and cost increase due to the need for precise control of RF power pulsing sequences, timing, and impedance matching
Solution Approach 1:
The patent replaces the traditional RF-based power supply system with a DC pulsed power supply system. Instead of using complex RF generators with impedance matching networks and pulsing control circuits, the invention uses a simple DC voltage source that can be rapidly switched on and off. This substitution eliminates the need for RF frequency generation, impedance matching, and complex pulsing sequence control, thereby significantly reducing system complexity while maintaining plasma processing capability
Solution Approach 2:
The patent extracts and removes the unnecessary RF generation and impedance matching components from the power supply system. By taking out the RF oscillator, matching network, and complex control circuitry, the invention leaves only the essential DC power delivery and pulsing control elements, simplifying the overall system architecture
2Manufacturing precision
If RF power is pulsed to improve etching process, then etching quality improves, but the control complexity increases due to the need for precise pulsing sequence, timing, voltage levels, and reflection control
Solution Approach 1:
The patent replaces the complex RF pulsing control system with a simple DC switching system. Instead of controlling RF power levels, frequency, and impedance during pulsing, the invention simply switches DC voltage on and off. This substitution maintains the ability to control plasma density and ion bombardment while eliminating the complexity of RF parameter control during pulsing sequences
Solution Approach 2:
The patent changes the fundamental parameter from RF power level control to DC voltage pulsing. By changing from continuous RF with duty cycle control to pulsed DC voltage, the system achieves similar plasma control effects through a simpler parameter control mechanism that only requires voltage magnitude and timing control
3Reliability
If RF power is supplied via match circuit and transmission line, then plasma etching can be performed, but hardware requirements increase due to large discrete capacitors, inductors, and sophisticated transmission lines
Solution Approach 1:
The patent extracts and removes the match circuit and transmission line components from the power delivery system. By taking out the large discrete capacitors, inductors, and sophisticated transmission lines required for RF power delivery, the invention simplifies the hardware architecture to basic DC power delivery components
Solution Approach 2:
The patent substitutes the RF transmission line infrastructure with simple DC power delivery wiring. Instead of requiring impedance-matched transmission lines, large capacitors, and inductors, the invention uses straightforward DC voltage delivery through simple conductors, dramatically reducing hardware complexity and manufacturing requirements
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 solution enables precise control of ion bombardment and ionization in plasma processing, improving etching efficiency and reducing the complexity and cost associated with traditional RF generators by allowing programmable pulsing patterns and dynamic adjustment of RF amplitudes.
Implementation Method 1
via a resonant circuit, amplifies it to high voltage
Implementation Method 2
via a network of diodes, and rectifies it back to DC
Implementation Method 3
A plasma processing system is provided that includes a chamber having a lower electrode coupled to a substrate support and an upper electrode coupled to ground. The plasma processing system having a plasma processing volume that is defined between the upper electrode and the lower electrode.
Data Source
AI summary
A plasma processing system is provided that includes a chamber having a lower electrode coupled to a substrate support and an upper electrode coupled to ground. The plasma processing system having a plasma processing volume that is defined between the upper electrode and the lower electrode. A direct current (DC) to direct current (DC) converter is provided to receive at an input a DC voltage input and supply at an output an amplified DC voltage signal that includes a radio frequency (RF) component. The DC voltage input follows a pulsing pattern that is digitally programmable. The output of the DC to DC convertor is connected to the lower electrode of the chamber. A controller is interfaced with the DC to DC converter to set the pulsing pattern. In one example, the DC to DC converter uses one of a bipolar or non-bipolar DC voltage supply and a RF generator is driven by a DC voltage supply. The RF generator is configured to produce a frequency ripple that defines the RF component.