Chip Resistor Protection Film for Low-Resistance Sulfur Blocking
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Solution Overview
Problem
Conventional chip resistors with silver upper surface electrodes deteriorate due to sulfurization in sulfide-containing environments, leading to faulty conductivity, and adding anti-sulfurization metals increases resistance, making it difficult to achieve both effective anti-sulfurization and low resistance.
Innovation Solution
A chip resistor design featuring a substrate with through holes and inner electrodes connecting the resistor body to lower surface electrodes, with an upper surface protection film covering the resistor body and electrodes, preventing sulfurization without the need for additional anti-sulfurization metals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If anti-sulfurization metal such as palladium is added to the upper surface electrodes, then anti-sulfurization properties are improved, but resistance value increases
Solution Approach 1:
A protection film is introduced as an intermediary layer between the sulfide-containing environment and the silver-based upper surface electrodes. This protection film prevents direct contact between sulfur and silver, eliminating the need to add anti-sulfurization metals like palladium to the electrodes themselves, thereby maintaining low resistance while providing anti-sulfurization protection.
Solution Approach 2:
The protection film serves as a sacrificial or disposable barrier that protects the valuable silver electrodes from sulfurization. Instead of making the electrodes themselves resistant to sulfur (which would require expensive metals), a separate protection layer is used that can be applied and potentially replaced if needed.
2Manufacturing precision
If silver is used as main component of upper surface electrodes, then low resistance is achieved, but sulfurization occurs in sulfide-containing environments
Solution Approach 1:
Different parts of the chip resistor are given different properties: the upper surface electrodes use silver for low resistance, while the protection film provides anti-sulfurization properties. This local differentiation allows each component to optimize its function without compromising the other.
Solution Approach 2:
The chip resistor employs composite material structure where silver-based electrodes are combined with a protection film material that has anti-sulfurization properties. This composite approach allows the system to achieve both low resistance (from silver) and sulfur resistance (from the protection film).
Data Source
AI summary
A chip resistor includes a resistor body, a first upper surface electrode, a second upper surface electrode, and an upper surface protection film on an upper surface of a substrate. The upper surface protection film covers the entire surface of the resistor body and the entire surface of the first upper surface electrode and the second upper surface electrode. The upper surface protection film includes a peripheral portion that is entirely in contact with the upper surface of the substrate.