Electronic Component Built-in Substrate With Through-Holes
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Solution Overview
Problem
Existing electronic component built-in substrates are prone to warpage due to thermal stress and contraction stress, caused by asymmetric structural design and lack of openings in the cavity bottom, which complicates the manufacturing process and increases costs.
Innovation Solution
A novel electronic component built-in substrate design featuring a cavity with through-holes in the bottom plate and a component mounting portion between them, allowing for symmetric insulation and stress distribution using the same insulating resin for both the upper and lower surfaces, eliminating the need for adhesive tape and simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cavity is formed in the core substrate with the bottom plate closed (no opening), then the capacitor can be mounted inside the cavity, but the core substrate is susceptible to contraction stress and likely to be warped
Solution Approach 1:
The bottom plate of the cavity is segmented by forming through-holes, transforming the closed bottom plate into an open structure. This segmentation allows the insulating resin to pass through and reduces the contraction stress concentration on the core substrate bottom plate, preventing warpage while still enabling capacitor mounting within the cavity.
2Reliability
If the structure around the capacitor in the thickness direction is asymmetric, then the capacitor can be mounted on the bottom plate of the cavity, but thermal stress is generated due to coefficient of thermal expansion difference, causing substrate warpage
Solution Approach 1:
The invention intentionally introduces asymmetry through the asymmetric arrangement of through-holes in the bottom plate. This asymmetric through-hole pattern creates an asymmetric stress distribution that counterbalances the thermal stress generated by the asymmetric capacitor mounting structure, thereby reducing overall substrate warpage.
3Ease of operation
If adhesive tape is used to temporarily stick the electronic component for mounting inside the cavity, then the component can be positioned, but the manufacturing process becomes complex and costs increase
Solution Approach 1:
The invention extracts and eliminates the adhesive tape from the manufacturing process. By forming through-holes in the bottom plate, the component can be directly mounted and fixed using the insulating resin that fills the cavity, removing the need for temporary adhesive tape and simplifying the manufacturing process.
4Reliability
If different insulating resins are used for upper and lower surfaces, then the insulating requirements are met, but the manufacturing process becomes more complex
Solution Approach 1:
The invention uses the same insulating resin for both the upper and lower surfaces of the cavity. The insulating resin is applied once to fill the entire cavity, providing uniform insulation properties throughout. This homogeneous approach simplifies the manufacturing process by eliminating the need to apply different resins to different surfaces.
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 design prevents warpage by offsetting thermal stress and distributing contraction stress, improving manufacturing efficiency and reducing costs by eliminating the need for temporary adhesive tape, while enhancing heat dissipation performance.
Implementation Method 1
during a heating process, if thermal stress is generated due to a difference in the coefficient of thermal expansion between elements, the substrate is likely to be warped
Implementation Method 2
since the bottom of the cavity of the core substrate has no opening, the core substrate is susceptible to contraction stress which is generated when a first insulating layer is formed to seal the capacitor, and thus the core substrate is likely to be warped
Data Source
AI summary
A substrate includes a core substrate; a cavity formed on an upper surface side of the core substrate; a bottom plate of the cavity formed integrally with the core substrate; a through-hole formed in the bottom plate, a component mounting portion formed at a portion of the bottom plate, an electronic component mounted on the component mounting portion so as to be disposed inside the cavity; a first insulating layer formed on an upper surface of the core substrate so as to cover an upper surface of the electronic component; and a second insulating layer formed on a lower surface of the core substrate so as to fill the through-hole and cover a lower surface of the electronic component. The cavity is filled with the first insulating layer and the second insulating layer. The first insulating layer and the second insulating layer are formed of the same insulating resin.