Non-shrink Varistor Substrate with Bonding Layer
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Solution Overview
Problem
The existing methods for integrating varistors with LED chips face challenges such as shrinkage deformation, non-uniform shrinkage rates, reduced mechanical strength, and increased manufacturing costs due to additional processing steps, which complicate the production of substrates that meet precise dimension standards and enhance bonding reliability.
Innovation Solution
A non-shrink varistor substrate is developed, comprising a reinforcement layer, a thin bonding layer, and multiple varistor layers with inner and outer electrode layers, where the thin bonding layer is formed using materials like SiO2, CuO, and Cr2O3, and the varistor layers are composed of ZnO-based materials with additives, enhancing bondability and mechanical strength through a non-shrink firing mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a substrate is used for integrating varistor with LED chip, then varistor protection function is achieved, but shrinkage deformation occurs during firing process
Solution Approach 1:
The patent employs a composite substrate structure consisting of a reinforcement layer (first substrate) and a varistor layer (second substrate) bonded together. The reinforcement layer provides dimensional stability and prevents shrinkage deformation during firing, while the varistor layer maintains its protective function. This composite structure resolves the contradiction by combining materials with different properties to achieve both reliability and manufacturing precision.
Solution Approach 2:
The patent introduces a bonding layer as an intermediary between the reinforcement layer and the varistor layer. This bonding layer facilitates reliable heterobonding between the two substrates while accommodating their different thermal expansion characteristics during firing. The bonding layer acts as a mediator that enables the varistor to maintain its protective function without causing shrinkage deformation.
2Manufacturing precision
If substrate material is changed to reduce shrinkage rate, then dimensional precision is improved, but bonding reliability between layers deteriorates
Solution Approach 1:
The bonding layer serves as an intermediary that enables reliable bonding between the reinforcement layer and varistor layer even when using materials with low shrinkage rates. This intermediate layer accommodates the different thermal and mechanical properties of the two substrates, ensuring bonding reliability while maintaining dimensional precision.
Solution Approach 2:
The patent modifies the bonding process parameters, specifically controlling the firing temperature and atmosphere, to achieve reliable bonding between layers while maintaining low shrinkage. By optimizing these parameters, the patent resolves the contradiction between dimensional precision and bonding reliability.
3Strength
If additional processing steps are added to enhance substrate properties, then mechanical strength is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent combines the reinforcement function and varistor integration function into a single composite substrate structure. The reinforcement layer not only provides mechanical strength but also prevents shrinkage deformation, eliminating the need for separate reinforcement treatments. This merging of functions reduces manufacturing complexity while improving mechanical strength.
Solution Approach 2:
By using a composite substrate structure, the patent achieves enhanced mechanical strength through the inherent properties of the reinforcement layer without requiring additional strengthening processes. The composite structure itself provides the necessary mechanical support, simplifying the manufacturing process.
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 solution ensures dimensional precision, enhances mechanical strength, and improves bondability, allowing for efficient heat dissipation and antistatic protection while maintaining a low shrinkage rate, thus addressing the limitations of existing substrate manufacturing processes.
Implementation Method 1
a thin bonding layer which is formed on the surface of the reinforcement layer
Implementation Method 2
an outer electrode layer which is formed on the first varistor layer and is electrically connected to the inner electrode layers by a conductive material loaded in a via hole
Implementation Method 3
electrically connected to the inner electrode layers by a conductive material loaded in a via hole formed through the first varistor layer, the thin bonding layer, and the reinforcement layer
Data Source
AI summary
Disclosed are a non-shrink varistor substrate and a method of manufacturing the same, wherein the non-shrink varistor substrate includes: a reinforcement layer formed of a ceramic material; a thin bonding layer formed on the surface of the reinforcement layer; a first varistor layer formed on the thin bonding layer and including a plurality of inner electrode layers therein; and an outer electrode layer formed on the first varistor layer and electrically connected to the inner electrode layers by a conductive material loaded in a via hole formed through the first varistor layer, the thin bonding layer and the reinforcement layer, and also wherein bondability and bonding reliability can be enhanced upon heterobonding of the reinforcement layer and the varistor layer.