PCB RF Probe Assembly With Stepped Insulator for Precise Sensing
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Solution Overview
Problem
Existing voltage and current probe assemblies for substrate processing systems face challenges in accurately measuring RF conductor voltages and currents due to sensitivity to mechanical tolerances, stray fields, and high-voltage creepage and clearance issues, leading to degraded isolation and crosstalk performance.
Innovation Solution
The implementation of a voltage and current probe assembly with a stepped insulator and integrated PCB-based components, including conductive pickup elements and shielding, which provides precise alignment, reduces mechanical errors, and minimizes stray field interference, while incorporating primary divider capacitors and differential transformer coupling for improved signal detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional voltage and current probe assemblies are used for RF conductor measurements, then basic measurement functionality is provided, but measurement precision degrades due to sensitivity to mechanical tolerances, stray fields, and high-voltage creepage issues
Solution Approach 1:
The patent introduces an insulator as an intermediary component that physically separates the PCB from the RF conductor, eliminating direct contact and reducing sensitivity to mechanical tolerances. The insulator provides a stable dielectric barrier that maintains consistent spacing between the pickup element and conductor, improving measurement precision while reducing harmful effects of mechanical variability
Solution Approach 2:
The patent replaces traditional mechanical probe contact systems with a PCB-based pickup element that couples to the RF conductor through electromagnetic fields via the insulator. This substitution eliminates mechanical wear and contact instability issues, providing more reliable and precise measurements that are less sensitive to mechanical tolerances
2Reliability
If traditional probe assemblies are used, then voltage and current sensing is achieved, but device complexity increases due to requirements for maintaining isolation and reducing crosstalk
Solution Approach 1:
The patent merges the voltage sensing function and current sensing function into a single integrated PCB assembly. The PCB contains both the voltage pickup element and the current sensing coil, eliminating the need for separate probe assemblies. This integration maintains isolation and crosstalk performance while reducing overall device complexity
Solution Approach 2:
The PCB assembly serves multiple functions simultaneously: it provides voltage sensing through the pickup element, current sensing through the coil, mechanical support via the insulator, and electromagnetic shielding. This multi-functionality reduces the number of separate components needed, simplifying the overall device structure while maintaining reliable isolation and crosstalk performance
3Ease of manufacture
If conventional probe designs are implemented, then basic sensing capability is provided, but manufacturing complexity increases due to precision alignment requirements and assembly difficulties
Solution Approach 1:
The insulator is designed with pre-formed features such as recesses, protrusions, or mounting holes that guide the PCB assembly into correct alignment with the RF conductor before final assembly. This preliminary structural preparation ensures proper positioning without requiring high-precision manual adjustment during manufacturing, easing the manufacturing process while maintaining alignment precision
Solution Approach 2:
The probe assembly is segmented into distinct modular components: the insulator, the PCB with pickup element, the current sensing coil, and mounting hardware. This segmentation allows each component to be manufactured and tested independently with standard tolerances, then assembled together to achieve the required overall alignment precision, reducing manufacturing complexity
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 solution achieves low-cost, high-precision voltage and current sensing with enhanced immunity to stray fields, reduced manufacturing complexity, and improved pulse responsiveness, addressing the limitations of existing probe assemblies.
Implementation Method 1
The pickup element is embedded in the one or more dielectric layers and disposed proximate the current carrying conductor
Implementation Method 2
The insulator is configured to surround a current carrying conductor
Data Source
AI summary
A probe assembly includes a stepped insulator and a printed circuit board. The insulator is configured to surround a current carrying conductor. The printed circuit board includes a main portion and an outward protruding portion. The outward protruding portion is implemented as a voltage probe and extends outward away from the main portion and into the insulator. The printed circuit board includes a conductive element, one or more dielectric layers, and a pickup element, where the conductive element extends through the one or more dielectric layers and is connected to the pickup element, and where the pickup element is embedded in the one or more dielectric layers and disposed proximate the current carrying conductor. The printed circuit board includes signal conditioning components connected to the conductive element of the voltage probe.