Interleaved Rectangular Balun Transformer for Uniform High-Power Etching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current semiconductor fabrication processes face challenges in achieving etch uniformity and high etch rates for shrinking features and higher aspect ratio geometries, particularly when using high radio frequency (RF) power levels.
Innovation Solution
The implementation of balun transformers with rectangular-shaped primary and secondary windings, which are interleaved in a spaced apart orientation, to efficiently transfer power to the transformer coupled plasma (TCP) coils in a plasma processing system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high RF power levels are used to increase etch rates, then productivity is improved, but etch uniformity deteriorates
Solution Approach 1:
A balun transformer is introduced as an intermediary device between the RF power source and the TCP coil. The transformer includes a primary winding connected to the RF power source and a secondary winding connected to the TCP coil, enabling efficient power transfer while maintaining plasma process stability. This intermediary component allows high power delivery without compromising etch uniformity across the wafer surface.
2Power
If rectangular conductors are used to increase surface area for RF coupling, then power transfer is improved, but device complexity increases
Solution Approach 1:
The patent transitions from traditional circular or toroidal coil geometries to a rectangular planar configuration for both primary and secondary windings. This dimensional change allows the windings to be arranged in an interleaved pattern where opposing sides face each other, maximizing the surface area for magnetic coupling. The rectangular geometry enables more efficient RF power transfer from the primary to secondary winding while maintaining a compact transformer structure suitable for semiconductor manufacturing equipment.
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 RF coupling between the primary and secondary coils, allowing for greater power transfer to the TCP coils, which improves etch uniformity and increases etch rates for finer features and higher aspect ratio geometries.
Implementation Method 1
balun transformers are used to efficiently transfer power to a transformer coupled plasma (TCP) coil
Data Source
AI summary
A balun transformer for use in powering an electrode coil of a semiconductor chamber is provided. In one example, the balun transformer includes a primary coil having a primary winding between a primary first end and a primary second end. The primary winding defined from a primary rectangular conductor. The balun transformer includes a secondary coil having a secondary winding between a secondary first end and a secondary second end. The secondary winding defined from a secondary rectangular conductor. The primary rectangular conductor and the secondary rectangular conductor are interleaved in a spaced apart orientation, such that one or two sides of each of the primary rectangular conductor and the secondary rectangular conductor are adjacent to one another.