Tunable Workpiece Biasing in Plasma Reactors
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Solution Overview
Problem
Current RF biasing techniques in semiconductor processing fail to provide tunable ion energy distribution, limiting the optimization of etching processes and understanding of ion energy effects on process results.
Innovation Solution
A system with a plasma chamber, a high voltage pulsed DC source directly coupled to the workpiece, and a second pulsed voltage source capacitively coupled, controlled by a biasing controller to tailor ion energy distribution by independently managing high, low, and medium ion energies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If single frequency RF biasing is used to accelerate ions, then ion energy distribution is well known and stable, but the distribution is not tunable and optimization of etching process is not possible
Solution Approach 1:
The patent divides the single voltage source into multiple independent pulsed voltage sources (first pulsed voltage source for high voltage, second pulsed voltage source for low/medium voltage). Each source can be independently controlled to generate different voltage pulses, enabling separate control of different ion energy components. This segmentation allows the system to achieve tunable ion energy distribution while maintaining manageable complexity through modular architecture.
Solution Approach 2:
The patent transitions from static single-frequency RF biasing to dynamic pulsed DC voltage sources with independently controllable parameters. The pulsed voltage sources can dynamically adjust pulse width, amplitude, and timing to tailor ion energy distribution in real-time, providing the adaptability needed for process optimization without requiring complete system redesign.
2Adaptability or versatility
If RF biasing techniques are used, then ion acceleration is achieved, but independent control of maximum ion energy and distribution of low/medium ion energies is not possible
Solution Approach 1:
The control system is segmented into a biasing controller that independently manages multiple pulsed voltage sources. The first pulsed voltage source controls maximum ion energy through high voltage pulses, while the second pulsed voltage source controls low/medium ion energy distribution through low/medium voltage pulses. This segmented control architecture enables independent adjustment of different ion energy parameters while maintaining operational simplicity through centralized control logic.
Solution Approach 2:
The patent employs parameter changes in the pulsed voltage sources to achieve independent control of ion energy characteristics. By varying pulse width, amplitude, and timing parameters of each voltage source, the system can independently tune maximum ion energy and low/medium ion energy distribution without changing the fundamental operation mode, simplifying the control approach while achieving versatile parameter adjustment.
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 precise control of ion energy distribution, allowing for optimized etching processes and improved understanding of ion energy effects, enhancing processing efficiency and throughput.
Implementation Method 1
generating a high voltage by a first pulsed voltage source and coupling the high voltage to a workpiece in a plasma chamber
Implementation Method 2
generating one or more of low and medium voltages by a second pulsed voltage source, coupling, capacitively, the one or more of low and medium voltages to the workpiece
Implementation Method 3
a plasma chamber that performs plasma processing on a workpiece
Implementation Method 4
Ion bombardment is often used as a source of activation energy for chemical and physical processes in etch and chemical vapor deposition (CVD) processes
Data Source
AI summary
Systems and methods for tunable workpiece biasing in a plasma reactor are provided herein. In some embodiments, a system includes: a plasma chamber that performs plasma processing on a workpiece, a first pulsed voltage source, coupled directly to a workpiece, a second pulsed voltage source, coupled capacitively to the workpiece, and a biasing controller comprising one or more processors, and memory, wherein the memory comprises a set of computer instructions that when executed by the one or more processors, independently controls the first pulsed voltage source and the second pulsed voltage source based on one or more parameters of the first pulsed voltage source and the second pulsed voltage source in order to tailor ion energy distribution of the flux of ions directed to the workpiece.