Triode Reactor RF Power Control for Plasma Uniformity
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Solution Overview
Problem
Current plasma processing systems for semiconductor wafer fabrication face challenges in achieving uniform deposition and etching due to inadequate control over ion energy and plasma chemistry, leading to non-uniform processes.
Innovation Solution
A wafer processing apparatus utilizing a triode reactor configuration with up to four RF power sources and a switch to independently control the top and bottom electrodes, allowing for precise adjustment of ion energy and plasma density through the application of different RF frequencies and power settings, enabling operation-by-operation configuration based on recipes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single plasma is generated in current plasma processing systems, then the system structure remains simple, but the control over radical separation, radical flux, ion energy, and ion flux is insufficient leading to non-uniform deposition and etching
Solution Approach 1:
The plasma generation system is segmented into two independent plasma sources: a first plasma generated between the first electrode and second electrode, and a second plasma generated between the third electrode and fourth electrode. This segmentation allows independent control of plasma parameters (radical flux, ion energy, ion flux) for each plasma source, enabling precise control over deposition and etching uniformity without requiring a single complex plasma system
Solution Approach 2:
The processing chamber is designed to generate and process two plasmas simultaneously using multiple electrode pairs, making the system capable of performing multiple functions: controlling radical separation, adjusting radical flux, regulating ion energy, and managing ion flux independently. This multi-functionality resolves the contradiction by achieving comprehensive parameter control within a unified chamber structure
2Manufacturing precision
If controls are inadequate in plasma processing systems, then the system operation remains simple, but non-uniform deposition and etching result on the wafer
Solution Approach 1:
The system employs dynamic control mechanisms where the first and second plasmas can be independently adjusted during operation. The first RF power source, second RF power source, third RF power source, and fourth RF power source can be varied independently to control plasma density, radical flux, and ion energy in real-time, enabling precise control over deposition and etching uniformity while maintaining operational flexibility
3Adaptability or versatility
If ion energy control is limited in the chamber, then the plasma generation system remains simple, but the control of desired process chemistry is insufficient
Solution Approach 1:
The system applies local quality control by creating distinct plasma regions with different characteristics. The first plasma between the first and second electrodes can be optimized for specific chemistry control, while the second plasma between the third and fourth electrodes can be optimized for other process requirements. This allows different process chemistries to be controlled independently in different spatial zones within the same chamber
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 configuration enhances control over plasma chemistry and uniformity, improving etching selectivity and uniformity, and allows for specific process conditions such as ultra-low ion energy and high-density plasma, optimizing wafer processing outcomes.
Implementation Method 1
a first radio frequency (RF) power source; a second RF power source; a third RF power source; a fourth RF power source... The first, second, and third power sources are coupled to the bottom electrode... the fourth RF power... causes the top electrode to be connected to the fourth RF power source
Data Source
AI summary
Methods, systems, and computer programs are presented for semiconductor manufacturing are provided. One wafer processing apparatus includes: a top electrode; a bottom electrode; a first radio frequency (RF) power source; a second RF power source; a third RF power source; a fourth RF power source; and a switch. The first, second, and third power sources are coupled to the bottom electrode. Further, the switch is operable to be in one of a first position or a second position, where the first position causes the top electrode to be connected to ground, and the second position causes the top electrode to be connected to the fourth RF power source.