Thermosetting Resin Electrodes for Ceramic Semiconductor Stability
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Solution Overview
Problem
Chip-type ceramic semiconductor electronic components experience significant variations in resistance value before and after mounting, due to oxidation and segregation of metal elements in external electrodes during high-temperature heat treatment, leading to increased resistance and potential cracking.
Innovation Solution
The use of a thermosetting resin that can be hardened at a lower temperature than conventional baking temperatures to form second external electrodes, which suppresses the oxidation and segregation of metal elements, thereby reducing the variation in resistance value and enhancing the component's reliability and solderability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-temperature heat treatment (baking) is used to form second external electrodes, then the electrodes are properly formed and hardened, but metal elements in first external electrodes undergo oxidation and segregation, causing resistance value variation
Solution Approach 1:
The patent changes the temperature parameter from conventional high-temperature baking (e.g., 800-1000°C) to low-temperature curing (e.g., 50-150°C). This parameter change allows the second external electrodes to be formed without causing oxidation and segregation of metal elements in the first external electrodes, thereby maintaining resistance value stability while achieving proper electrode formation and hardening.
2Ease of manufacture
If conventional high-temperature baking is used, then second external electrodes are formed, but flexure strength decreases due to cracking from thermal stress
Solution Approach 1:
The patent changes the temperature parameter from high-temperature baking to low-temperature curing (50-150°C). This eliminates thermal stress that causes cracking in the ceramic body, thereby maintaining flexure strength while still achieving proper formation and hardening of the second external electrodes through the low-temperature curing process.
3Reliability
If low-temperature curing is used to form second external electrodes, then oxidation and segregation are suppressed, but the curing process must be optimized to ensure proper hardening
Solution Approach 1:
The patent changes the temperature parameter to a low range (50-150°C) and optimizes the curing time parameter (e.g., 1-24 hours). This combination of parameter changes enables proper hardening of the second external electrodes through chemical cross-linking of the resin material, achieving reliable resistance value stability while maintaining manageable process complexity through well-established low-temperature curing technologies.
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
This approach results in a chip-type ceramic semiconductor electronic component with a smaller variation in resistance value before and after mounting, improved flexure strength, reduced manufacturing costs, and enhanced performance by preventing the increase in resistance value at room temperature, particularly beneficial for PTC thermistors.
Implementation Method 1
the use of a resin material that can be hardened at a lower temperature than the temperature for the above-mentioned heat treatment such as baking
Implementation Method 2
heat treatment at high temperatures such as baking can partially oxidize metal elements contained in first external electrodes
Implementation Method 3
the metal elements contained in the first external electrodes can tend to be partially diffused and segregate within the first external electrodes
Data Source
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AI summary
Provided is a chip-type ceramic semiconductor electronic component where the variation in the rate of change in resistance value is small between before and after mounting. Provided is a chip-type ceramic semiconductor electronic component including: a ceramic body including a ceramic semiconductor; a pair of first external electrodes formed on both end surfaces of the ceramic body; and a pair of second external electrodes formed to cover the first external electrodes and extend partially on side surfaces of the ceramic body, where the second external electrodes include a conductive agent and a thermosetting resin hardened at a temperature of 500°c or lower.