Adjustable Phase Shift Assembly for RF Generator Synchronization
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Solution Overview
Problem
In semiconductor processes, multiple RF generators interact with each other, causing unwanted variations in etching and deposition rates and uniformity due to capacitive and inductive coupling, leading to inefficiencies in twin-chamber designs.
Innovation Solution
An adjustable phase shift assembly with a two-dimensional trace is used to synchronize RF generators, allowing for automatic adjustments in the phase shift between RF generators based on metrology data, minimizing coupling effects and optimizing wafer performance parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple RF generators are used for plasma generation and substrate biasing, then process versatility and plasma quality are improved, but unwanted interactions between generators cause variations in etching and deposition rates
Solution Approach 1:
An adjustable phase shift assembly is introduced as an intermediary component between multiple RF generators to control and adjust the phase relationship between them. This mediator allows optimization of the interaction between generators, eliminating unwanted variations in etching and deposition rates while maintaining process versatility
Solution Approach 2:
The phase shift between RF generators is adjusted as a controllable parameter to optimize process outcomes. By changing the phase relationship between generators through the adjustable phase shift assembly, the system achieves uniform etching and deposition rates while maintaining multiple process capabilities
2Reliability
If separate RF generators with separate power supplies are used for twin chambers, then system independence is improved, but RF generator interactions still cause process variations
Solution Approach 1:
The adjustable phase shift assembly serves as a mediator between independently powered RF generators, allowing control over their interactions. This enables twin chambers to maintain independence while achieving uniform process results through controlled phase relationships
3Ease of operation
If synchronized signals are used between RF generators, then timing coordination is improved, but capacitive and inductive coupling causes unwanted effects
Solution Approach 1:
The phase shift assembly acts as an intermediary that manages synchronized signals between RF generators. It allows timing coordination to be maintained while controlling the capacitive and inductive coupling effects that cause harmful interactions
Solution Approach 2:
The phase relationship parameter is adjusted to optimize signal synchronization while minimizing harmful coupling effects. By changing the phase shift between generators, the system achieves coordinated operation without the unwanted capacitive and inductive interactions
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 enhances the uniformity and throughput of semiconductor processes by compensating for RF generator interactions, enabling the use of a common frequency for both plasma and bias power sources, thereby improving deposition and etch rates.
Implementation Method 1
adjustable phase shift assembly with a two-dimensional trace and an adjustable contact point wherein the adjustable phase shift assembly is connected to the cable and configured to alter at least one wafer performance parameter by changing a phase shift relationship between the first RF frequency generator and the second RF frequency generator
Data Source
AI summary
Methods and apparatus for controlling a semiconductor process leverage phase shifting between at least two RF generators to improve wafer performance parameters. In some embodiments, an apparatus may include a first radio frequency (RF) generator, a second RF frequency generator, a cable connected between the first RF generator and the second RF generator wherein the cable is configured to synchronize the first RF generator and the second RF generator, and an adjustable phase shift assembly with a two-dimensional trace and an adjustable contact point. The adjustable phase shift assembly is connected to the cable and configured to alter at least one water performance parameter by changing a phase shift relationship between the first RF frequency generator and the second RF frequency generator.