SiC-ZnO Suppressor for Low-Voltage ESD Protection
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Solution Overview
Problem
Conventional suppressors are inadequate in protecting internal circuits from static electricity at low ESD voltages and are prone to shorts due to the reactivity of discharge materials with internal electrodes, particularly when made with LTCC, varistor calcination powder, silver, and glass.
Innovation Solution
A suppressor with a discharge material comprising a SiC—ZnO-based component, where SiC and ZnO are reacted to form an insulating layer on the surface of SiC, preventing shorts and enhancing ESD resistance, and the material is printed on internal electrodes and co-fired with a LTCC material for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional discharge materials (varistor calcination powder, silver, glass) are used in LTCC suppressors, then low-temperature sintering is achieved, but ESD resistance is weak and shorts occur upon DC loading
Solution Approach 1:
The patent uses a composite discharge material consisting of SiC particles coated with ZnO layer. This composite structure combines the low-temperature sintering capability of ZnO with the high ESD resistance and electrical stability of SiC, resolving the contradiction between easy manufacture and reliability.
Solution Approach 2:
The patent changes the chemical composition parameters of the discharge material from conventional varistor calcination powder to SiC-ZnO composite. By controlling the particle size, ZnO coating thickness, and SiC content, the material achieves both low-temperature sintering and superior ESD protection performance.
2Ease of manufacture
If discharge material is made with reactive components (silver, glass, varistor powder), then manufacturing is simplified, but the discharge material reacts with internal electrodes causing shorts
Solution Approach 1:
The ZnO coating acts as an intermediary layer between the SiC core and the internal electrodes. This intermediate ZnO layer prevents direct contact and chemical reaction between the discharge material and electrodes, eliminating the harmful reactivity while maintaining manufacturing simplicity.
Solution Approach 2:
The patent converts the potential harm of material reactivity into a benefit by using ZnO's properties. ZnO provides both the low-temperature sintering capability and forms a protective barrier, turning what could be a reactive hazard into a protective feature that prevents electrode degradation.
3Reliability
If conventional suppressors are used, then basic protection is provided, but suppression performance at low ESD voltage (3 KV or less) is insufficient
Solution Approach 1:
The patent applies local quality by creating a non-uniform discharge material structure where ZnO is concentrated on the surface particles and SiC forms the core. This localized distribution allows the material to respond effectively to low-voltage ESD events while maintaining stability under normal operating conditions.
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
The SiC—ZnO reaction layer provides superior insulating properties, preventing shorts during DC loading and enhancing ESD resistance, allowing for precise control of capacitance and manufacturing of suppressors with low capacitance values.
Implementation Method 1
ZnO is reacted with the surface of SiC to form an insulating layer
Implementation Method 2
The discharge material may be fired using thermal treatment, so that a SiC—ZnO reaction layer is formed on the surface of SiC
Implementation Method 3
A varistor is widely utilized as a protective device for protecting important electronic parts and circuits from overvoltage (surge voltage) and static electricity
Implementation Method 4
an ESD absorber is configured such that a predetermined empty space is formed between internal electrodes to block comparatively large overvoltage or overcurrent
Data Source
AI summary
This invention relates to a suppressor, including an element having sheets printed with a first internal electrode and a second internal electrode, and a discharge material disposed in a gap between the first internal electrode and the second internal electrode, wherein the discharge material is composed of a SiC—ZnO-based component, in which ZnO is reacted with the surface of SiC, thereby imparting much higher insulating properties and improving ESD resistance.