Microresistor Temperature Coefficient Control via Electrode Gap and Protective Layer Coverage
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Solution Overview
Problem
Current micro-resistors have a large temperature coefficient of electrical resistance, leading to unpredictable resistance changes with temperature, uneven resistance distribution, and reduced product yield due to dispersed thickness of plated copper, which affects product quality.
Innovation Solution
A micro-resistor design with a resistor material layer, electrode set, and protective layers, where the difference between opening and coverage sizes is minimized to maintain a temperature coefficient of electrical resistance below 150 ppm/°C, ensuring even resistance distribution across different resistance ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional resistor design with copper electrodes and lithographic techniques is used, then the resistor pattern can be formed, but the temperature coefficient of electrical resistance becomes too large causing resistance to be susceptible to temperature changes
Solution Approach 1:
The patent changes the geometric parameters of the resistor pattern, specifically the relationship between opening size and coverage size of protective layers, to control the temperature coefficient of electrical resistance. By optimizing these dimensional parameters, the invention achieves a temperature coefficient of not greater than 150 ppm/°C, significantly improving resistance stability against temperature variations.
2Manufacturing precision
If the thickness distribution of plated copper is not controlled, then the resistance becomes too dispersed affecting product yield, but controlling it requires precise manufacturing processes
Solution Approach 1:
The patent applies protective layers before final resistance measurement and trimming. These protective layers are designed with specific coverage sizes that compensate for variations in plated copper thickness, ensuring uniform resistance distribution even when thickness varies. This preliminary protective action prevents resistance dispersion and maintains high product yield.
3Measurement precision
If trimming is performed to fine-tune resistance, then the target resistance is achieved, but the trimming time increases and product integrity may be compromised
Solution Approach 1:
The protective layers are applied in advance before the trimming process. This preliminary protection allows for more aggressive or precise trimming operations without compromising product integrity, as the protective layers shield the resistor material during the trimming process while still allowing the trimming tool to access the resistance path for fine-tuning.
4Object-affected harmful factors
If the difference between opening size and coverage size is not controlled, then the temperature coefficient becomes too large, but controlling this difference requires precise manufacturing
Solution Approach 1:
The patent establishes specific parameter relationships between opening size and coverage size of protective layers. By defining these dimensional parameters and their differences, the invention creates a design rule that achieves low temperature coefficient (≤150 ppm/°C) while being manufacturable with standard precision capabilities.
Data Source
AI summary
A micro-resistor includes a resistor material layer, an electrode set and a first protective layer. The electrode set includes a first electrode and a second electrode to define an opening which exposes the resistor material layer. A space between the first electrode and the second electrode represents an opening size. The first protective layer covers the opening completely and has a coverage size along a direction parallel with the space. The micro-resistor has a resistance of less than 5 milliohm and the difference of the opening size and the coverage size is less than 3100 micrometer to make the temperature coefficient of electrical resistance of the micro-resistor not greater than 150 ppm/° C.