Planar Electromagnetic Filter for RF Backflow Isolation
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Solution Overview
Problem
In semiconductor processes using plasma, high-voltage RF power generated in the plasma chamber can flow back into the heater control unit through the heater, causing process deviations and reducing precision and yield.
Innovation Solution
An electromagnetic filter with a housing made of conductive metal, an insulating base plate, and a flat wire coil inductor is used to filter high-voltage RF power. The filter is designed to adjust parasitic capacitance and minimize inductance interference, allowing for precise control of inductance and improved filtering performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a conventional electromagnetic filter is used to block high-voltage RF power, then RF power filtering is achieved, but the filter size is large and integration is low
Solution Approach 1:
The patent transitions from conventional three-dimensional coil structures to a two-dimensional planar inductor design. The inductor is formed as a flat pattern on a substrate, changing the spatial dimensionality of the filtering component. This dimensional reduction enables compact integration while maintaining the essential electromagnetic filtering function through optimized trace geometry and layout patterns.
Solution Approach 2:
The electromagnetic filter is divided into multiple functional segments: a planar inductor section with trace patterns, a capacitor section with electrode structures, and connecting transmission line sections. Each segment performs a specific filtering function and can be independently optimized. The segmented design allows for compact arrangement and efficient signal flow while achieving the required RF power blocking performance.
2Reliability
If the inductance of the filter is adjusted for optimal filtering, then filtering performance is improved, but the adjustment process is complex and time-consuming
Solution Approach 1:
The inductance value is optimized by varying geometric parameters of the planar inductor during the design stage, such as trace width, trace length, trace spacing, and number of winding patterns. These dimensional parameters directly control the inductance value, allowing for precise tuning of filtering characteristics. The relationship between geometric parameters and inductance is established through electromagnetic simulation and analytical models, enabling direct design of the desired inductance value without complex adjustment mechanisms.
3Manufacturing precision
If high-voltage RF power is blocked from flowing back to the heater control unit, then process precision is improved, but the filter design becomes more complex
Solution Approach 1:
Multiple filtering functions are merged into a single integrated planar structure. The inductor and capacitor elements are combined in a compact arrangement on the same substrate, with transmission lines connecting them to form a complete filtering network. This merged design achieves high-voltage RF power blocking, noise filtering, and impedance matching in one component, preventing process deviations without requiring multiple separate devices.
Solution Approach 2:
The electromagnetic filter acts as an intermediary component between the heater control unit and the plasma chamber. It is positioned in the signal path to block harmful high-voltage RF power from reaching the heater control unit while allowing necessary control signals to pass through. The filter structure includes isolation elements and shielding features that mediate the electromagnetic interaction, protecting the control unit from RF interference and plasma-induced noises.
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
The electromagnetic filter effectively prevents high-voltage RF power from flowing back into the heater control unit, reducing process deviations and improving the precision and yield of semiconductor processes. The filter's design allows for miniaturization, high output, and precise adjustment of inductance, enhancing its filtering performance.
Implementation Method 1
an inductor including a flat wire coil having a center axis disposed perpendicular to an upper surface of the base plate and installed on the upper surface of the base plate to be connected to the output port
Data Source
AI summary
The present disclosure provides an electromagnetic filter structure. An electromagnetic filter according to the present disclosure includes a housing made of an electrically conductive metal material, an input port and an output port each provided on one of both facing side surfaces of the housing, a base plate made of an electrically insulating material and installed above a bottom surface of the housing, an inductor including a flat wire coil having a center axis disposed perpendicular to an upper surface of the base plate and installed on the upper surface of the base plate to be connected to the output port, and a plurality of conductive plates fixed to the upper surface of the base plate and connecting between the input port and the inductor and between the output port and the inductor.