Chip Resistor Electrode Segmentation for Sulfurization Resistance
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Solution Overview
Problem
Chip resistors with silver-palladium electrodes face challenges in maintaining high sulfurization resistance and accurate resistance value adjustment, especially at low resistance values, due to variations in electrode specific resistance and contact resistances during the trimming process.
Innovation Solution
The chip resistor design includes a pair of electrodes with a main electrode layer containing 10 weight % or more palladium and an auxiliary electrode layer with 95 weight % silver, laminated in sequence, where the auxiliary layer is exposed and not covered by the insulating film, allowing for precise resistance value adjustment by abutting probe electrodes against the auxiliary electrode layers during trimming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrode is made of silver-palladium-based material containing 10 weight % or more of palladium to suppress sulfurization, then sulfurization resistance is improved, but specific resistance increases making resistance value measurement unstable
Solution Approach 1:
The electrode is divided into two distinct layers: a main electrode layer containing silver and 10 weight % or more of palladium for sulfurization resistance, and an auxiliary electrode layer with lower specific resistance for stable measurement. This segmentation allows each layer to fulfill its specific function without compromise.
Solution Approach 2:
Different regions of the electrode structure are assigned different material properties. The main electrode layer has high sulfurization resistance due to high palladium content, while the auxiliary electrode layer has low specific resistance for measurement stability. This local differentiation of material quality resolves the contradiction between sulfurization resistance and measurement precision.
2Reliability
If the electrode contains high palladium content for sulfurization resistance, then sulfurization resistance is improved, but contact resistance influences measurement accuracy
Solution Approach 1:
The electrode structure is segmented into a main electrode layer for sulfurization resistance and an auxiliary electrode layer for low contact resistance. The auxiliary layer's low specific resistance minimizes contact resistance effects during trimming and measurement operations, enabling precise resistance value adjustment.
Solution Approach 2:
The auxiliary electrode layer acts as an intermediary between the measurement/trimming probe and the high-resistance main electrode layer. This intermediary layer provides a low-resistance contact path, reducing the influence of contact resistance on manufacturing precision while allowing the main layer to maintain sulfurization resistance.
3Measurement precision
If probe electrodes contact the electrode for resistance measurement, then resistance value can be measured, but variation in probe interval and contact resistance cause measurement instability
Solution Approach 1:
The auxiliary electrode layer is specifically designed with low specific resistance at the regions where probe electrodes make contact. This local quality optimization ensures that contact resistance is minimized at the measurement interface, making the measurement process stable and reliable despite variations in probe interval or contact conditions.
Data Source
AI summary
A chip resistor including an insulating film covering a resistor making contact with a pair of electrodes formed on an upper surface of an insulating substrate and a method for manufacturing same are provided. Both electrodes include a main electrode layer that contains silver as a main metal component an 10 weight % or more of palladium as another metal component, and an auxiliary electrode layer lower in specific resistance than the main electrode layer, a laminate part where the auxiliary electrode layer and the main electrode layer are laminated in order on a single surface of the insulating substrate; and an exposed part of the auxiliary electrode layer where a part of the auxiliary electrode layer is not covered with the main electrode layer on a far side from the resistor, and part that extend from a near side to the far side with respect to the resistor.