Thermistor Electrode Structure to Block Plating Solution Penetration
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Solution Overview
Problem
The manufacturing of thermistors is challenging due to damage during handling of strip-shaped thermistor materials, uneven conductive paste application, and potential penetration of plating solutions into electrode portions, leading to instability and resistance value changes.
Innovation Solution
A method involving the formation of a base electrode layer on a thermistor wafer, followed by cutting into chips, applying a protective oxide film, and creating a two-layer electrode structure with a cover electrode layer, ensuring electrical conductivity and preventing plating solution penetration through heat treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If thermistor wafers are cut into strip shapes, then chips can be formed for manufacturing, but the strip-shaped thermistor materials are easily damaged during handling and manufacturing efficiency decreases
Solution Approach 1:
The base electrode layer is formed on the thermistor wafer before cutting into chips. This preliminary action strengthens the wafer structure, preventing damage during subsequent handling and cutting operations while maintaining manufacturing efficiency
2Device complexity
If a single-layer electrode structure is used, then the manufacturing process is simple, but the plating solution penetrates into the electrode portion causing deterioration
Solution Approach 1:
A two-layer electrode structure comprising a base electrode layer and a cover electrode layer is employed. The base layer provides electrical conductivity while the cover layer acts as a barrier against plating solution penetration, preventing deterioration and maintaining reliability
3Ease of manufacture
If conductive paste is applied unevenly or contaminated with foreign matter, then the electrode portions develop pores creating a porous structure, but this leads to plating solution penetration and resistance value changes
Solution Approach 1:
The cover electrode layer is applied over the base electrode layer to compensate for potential defects such as pores or contamination in the base layer. This protective layer prevents plating solution penetration even if the base layer has manufacturing imperfections
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 method enhances handling and manufacturing efficiency, stabilizes thermistor characteristics, and prevents plating solution penetration, maintaining consistent resistance values.
Implementation Method 1
forming a base electrode layer by applying and sintering a conductive paste on both surfaces of a thermistor wafer
Implementation Method 2
cutting the thermistor wafer on which the base electrode layer is formed to form chips
Implementation Method 3
forming a cover electrode layer by applying and sintering a conductive paste on a surface of the protective film
Implementation Method 4
performing a heat treatment such that the base electrode layer and the cover electrode layer are electrically conductive
Data Source
AI summary
The present invention is provided with a base electrode layer forming step of forming a base electrode layer on both surfaces of a thermistor wafer formed of a thermistor material, a chip forming step of obtaining a thermistor chip with a base electrode layer by cutting the thermistor wafer to form chips, a protective film forming step of forming a protective film formed of an oxide on an entire surface of the thermistor chip with a base electrode layer, a cover electrode layer forming step of forming a cover electrode layer by applying and sintering a conductive paste on an end surface of the thermistor chip with a base electrode layer, and a conduction heat treatment step of performing a heat treatment such that the base electrode layer and the cover electrode layer are electrically conductive, in which the electrode portion is formed.