Microwave Plasma Generating Device With Insulated Electrode
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Solution Overview
Problem
Conventional microwave plasma generating devices face challenges in achieving high-quality layer deposition at high deposition rates due to low ion energy, which is difficult to set and maintain, especially with moving substrates, leading to lower layer quality.
Innovation Solution
Incorporating a plasma electrode insulated from the chamber wall and capable of DC, LF, or HF voltage application within the plasma chamber, allowing the microwave plasma to partially assume the function of the outer conductor, thereby increasing ion energy and enabling higher layer density and quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If substrate bias voltage is increased to accelerate ions and increase layer density, then layer quality improves, but reliable setting of desired substrate prestress becomes difficult especially with moving substrates
Solution Approach 1:
The patent introduces a plasma electrode as an intermediary component between the microwave plasma source and the substrate. This electrode allows independent control of ion energy through applied voltage while maintaining stable substrate prestress, resolving the contradiction by mediating the interaction between plasma and substrate.
Solution Approach 2:
The patent segments the electrical potential control into two independent parts: substrate prestress control and ion energy control. The plasma electrode handles ion energy acceleration while the substrate carrier maintains prestress, allowing both parameters to be optimized independently without interference.
2Productivity
If microwave plasma is used for high deposition rates, then productivity increases, but ion energy remains relatively low leading to lower layer quality
Solution Approach 1:
The patent changes the energy state parameter of the plasma by applying additional voltage to the plasma electrode. This transforms the low-energy microwave plasma into a high-energy plasma that can achieve both high deposition rates and high layer quality simultaneously.
Solution Approach 2:
The patent uses pulsed microwave operation combined with DC voltage on the plasma electrode. During microwave pulses, high ion flux is generated for rapid deposition; during off periods, the DC voltage maintains ion acceleration for quality control, creating a periodic cycle that achieves both goals.
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 allows for adjustable ion energy and improved layer quality by shifting the electrical potential of the microwave plasma relative to the substrate, enhancing deposition rates and overcoming energetic barriers during annealing processes.
Implementation Method 1
at least one microwave generating device provided outside the plasma chamber for generating microwaves
Implementation Method 2
in the plasma chamber an exit of microwaves from the microwave line for generation a microwave plasma is provided in the interior of the plasma chamber
Implementation Method 3
at least one plasma electrode which is electrically insulated from the chamber wall and can be subjected to a DC, LF or HF voltage is provided in the interior of the plasma chamber, coaxially with the inner conductor, with which the microwave plasma can be electrically contacted
Data Source
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AI summary
The invention relates to a microwave plasma generating device with a plasma chamber. At least one microwave generating device is provided outside of the plasma chamber, and the microwaves of said microwave generating device are coupled into the plasma chamber via at least one microwave incoupling device. The microwave incoupling device has an inner conductor which leads into the plasma chamber through at least one chamber wall of the plasma chamber, an insulating tube which encloses the inner conductor and separates the inner conductor from an interior of the plasma chamber, and at least one outer conductor which leads into the plasma chamber through the at least one chamber wall and which is coaxial to the inner conductor but is not provided over the entire circumference of the inner conductor. The outer conductor has at least one outer conductor end in the plasma chamber. The inner conductor and the outer conductor form a microwave line, an outlet of microwaves out of the microwave line being provided in the plasma chamber in order to generate a microwave plasma in the interior of the plasma chamber. According to the invention, at least one plasma electrode which is electrically insulated from the chamber wall and to which a DC, NF, or HF voltage can be applied is provided in the interior of the plasma chamber coaxially to the inner conductor. The microwave plasma can be brought into electric contact with the plasma electrode such that the function of the outer conductor can be transferred at least partly to the microwave plasma. The invention further relates to a method for operating such a microwave plasma generating device.