Ceramic Composite Multilayer Substrate with Resin Impregnation
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Solution Overview
Problem
Existing ceramic multilayer substrate manufacturing methods face challenges such as firing shrinkage, porosity issues, and layer separation due to thermal expansion coefficient differences, leading to substrate warpage, cracking, and complex manufacturing processes.
Innovation Solution
A ceramic composite multilayer substrate is developed with a laminate structure including a first ceramic layer, a second ceramic layer to suppress firing shrinkage, and a resin/ceramic composite layer impregnated with resin, which is formed by firing a non-fired composite laminate with a third ceramic green layer on the surface, ensuring uniform porosity and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a non-sintering inorganic composition layer is sandwiched between ceramic green sheets and fired, then the multilayer ceramic substrate can be formed with low-temperature sintering, but the porosity near the interface becomes small and resin cannot be sufficiently charged
Solution Approach 1:
The patent uses a porous sintered compact layer instead of a non-sintering inorganic composition layer. This porous structure maintains adequate porosity near the interface to allow resin charging while still providing the necessary structural support and thermal expansion matching. The porous nature enables resin penetration without requiring excessive porosity throughout the entire layer.
Solution Approach 2:
The patent changes the physical and chemical parameters of the intermediate layer by using a sintered compact material with controlled porosity rather than a non-sintering inorganic composition. This parameter change allows the layer to maintain structural integrity at low firing temperatures while preserving sufficient porosity for resin impregnation.
2Stability of the object's composition
If the thermal expansion coefficient of the ceramic substrate is adjusted to match either the ceramic substrate or printed-circuit board, then layer separation can be prevented, but thermal shock may cause layer separation or cracks at the interface
Solution Approach 1:
The patent applies local quality by creating a gradient structure where the thermal expansion coefficient varies through the thickness of the resin laminate. The first resin layer (adjacent to ceramic substrate) has a thermal expansion coefficient closer to the ceramic substrate, while the second resin layer (adjacent to printed-circuit board) has a thermal expansion coefficient closer to the printed-circuit board. This gradual transition prevents both layer separation and thermal shock cracking.
Solution Approach 2:
The patent changes the thermal expansion coefficient parameter gradually through the resin laminate thickness rather than maintaining a uniform value. This parameter gradient allows the structure to accommodate thermal expansion differences between ceramic substrate and printed-circuit board while resisting thermal shock.
3Stability of the object's composition
If multiple resin layers with different thermal expansion coefficients are laminated, then thermal expansion coefficient gradient can be achieved, but the manufacturing process becomes complex and productivity decreases
Solution Approach 1:
The patent segments the resin laminate into multiple layers with different thermal expansion coefficients. The first resin layer contains a first ceramic powder with a first thermal expansion coefficient, while the second resin layer contains a second ceramic powder with a second thermal expansion coefficient. This segmentation achieves the desired thermal expansion gradient while maintaining manufacturing feasibility through a systematic lamination process.
4Length of moving object
If the ceramic substrate thickness is reduced to decrease device height, then integration density increases, but the ceramic substrate becomes more prone to warpage and cracking
Solution Approach 1:
The patent uses composite materials by combining the thin ceramic substrate with a multi-layer resin laminate containing different ceramic powders. This composite structure provides mechanical support and stress distribution that prevents warpage and cracking in the thin ceramic substrate while maintaining the reduced device height. The resin layers act as a reinforcing matrix that compensates for the reduced thickness of the ceramic substrate.
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 results in a high-reliability substrate with excellent flatness, reduced pores, and simplified manufacturing, eliminating layer separation and warpage, while maintaining mechanical strength and thermal expansion coefficient matching with printed-circuit boards.
Implementation Method 1
a second ceramic layer which is disposed so as to contact the first ceramic layer and to suppress firing shrinkage in a plane direction of the first ceramic layer
Implementation Method 2
a resin/ceramic composite layer in which a porous ceramic layer is impregnated with a resin
Implementation Method 3
firing the non-fired composite laminate under the conditions where at least the first ceramic green layer is sintered
Data Source
AI summary
A high-reliability ceramic composite multilayer substrate that has excellent flatness and few remaining pores, can be produced at a low cost while simplifying the manufacturing process, and can eliminate layer separation or separation from a mother board. The ceramic composite multilayer substrate includes a laminate containing a first ceramic layer and a second ceramic layer that is disposed so as to contact the first ceramic layer and suppresses firing shrinkage in the plane direction of the first ceramic layer. The laminate includes a resin/ceramic composite layer in which porous ceramic is impregnated with a resin formed on at least one principal surface of the laminate.