Current Sensor With Through-Silicon Interconnects and Isolation Layer
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Solution Overview
Problem
Current sensors face challenges in achieving high sensitivity, immunity to temperature variations, high dielectric strength, and low production costs while maintaining reliability and ease of fabrication.
Innovation Solution
A current sensor design featuring a leadframe-based current conductor with a semiconductor chip mounted on it, utilizing through silicon connections and isolation layers for enhanced electrical connections and dielectric strength, along with wire bonding for robustness, and strategically placed electrical terminals to minimize ohmic resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional leadframe-based current sensor design is used, then the structure is simple and easy to manufacture, but the dielectric strength between the current conductor and electronics is insufficient
Solution Approach 1:
The patent introduces an intermediary isolation layer (ceramic plate or plastic housing material) between the current conductor and the semiconductor chip electronics. This isolation layer acts as a mediator that provides the required dielectric strength (2-4 kV) while allowing the sensor to maintain its compact IC housing structure and ease of manufacture. The isolation layer is positioned to electrically insulate the high-voltage current path from the low-voltage sensing electronics.
2Device complexity
If the semiconductor chip is mounted directly on the leadframe without isolation layers, then the device complexity is reduced, but the immunity to temperature variations and stress is insufficient
Solution Approach 1:
The patent employs composite materials by combining the semiconductor chip with an isolation layer (ceramic or plastic) and mounting it on the leadframe. This composite structure provides thermal isolation between the current-conducting path and the sensitive electronics, improving immunity to temperature variations and thermal stress. The isolation layer acts as a thermal barrier while maintaining electrical connectivity through controlled interfaces, enhancing overall device reliability without significantly increasing 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 design achieves high reliability, robustness against thermal stress, and low production costs while maintaining high dielectric strength and sensitivity, reducing ohmic resistance and electromagnetic interference.
Implementation Method 1
Current sensors, which detect the magnetic field generated by the current
Data Source
AI summary
A current sensor comprises a current conductor having a first portion, a measuring portion and a second portion, the first portion including one or more first electrical terminals and the second portion including one or more second electrical terminals. The current sensor further comprises third electrical terminals and a semiconductor chip. The semiconductor chip has one or more magnetic field sensors disposed in the active surface, is mounted on the current conductor with an active surface facing the current conductor. The active surface comprises first contacts. The semiconductor chip comprises electrical through silicon connections disposed over and electrically connected to the first contacts. A backside of the semiconductor chip comprises second contacts, each of the second contacts electrically connected to one of the electrical through silicon connections. Wire bonds electrically connect the second contacts with the third electrical terminals.