Wiring Substrate Pad Opening for Uniform Insulation
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Solution Overview
Problem
The existing wiring substrates face issues with unequal thickness of the second insulation layer over electronic components, leading to varying via-hole depths and reduced connection reliability due to uneven resin distribution in concave portions, affecting the electrical connection between the wiring pattern and the component pads.
Innovation Solution
A wiring substrate design where a pad with a predetermined opening is exposed in a cavity, allowing the second insulation layer to fill the gap between the electronic component and the cavity, ensuring uniform thickness and improved connection reliability by determining the opening's position and size based on the volume distribution of concave portions on the electronic component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the second insulation layer is formed by resin to cover the electronic components, then the concave portions are filled with resin, but the thickness of the second insulation layer becomes unequal depending on the volume distribution of the concave portions
Solution Approach 1:
The patent applies local quality by creating concave portions with specific volume distributions at different locations on the electronic component surfaces. By controlling the volume of concave portions locally, the resin flow and distribution are regulated to achieve uniform second insulation layer thickness across the substrate, thereby resolving the contradiction between filling concave portions and maintaining thickness uniformity.
2Reliability
If the thickness of the second insulation layer is increased to cover deeper via-holes, then the via-hole depth increases, but the area of the bottom portion of the via-hole decreases
Solution Approach 1:
The patent changes the volume parameter of concave portions to control resin flow distribution. By adjusting the volume of concave portions in different regions, the resin fills areas to achieve uniform second insulation layer thickness, which maintains consistent via-hole depths and bottom areas, thereby preserving connection reliability without reducing via-hole bottom area.
3Manufacturing precision
If the via-hole depth increases due to thicker second insulation layer, then the insulation coverage is improved, but the connection reliability through the via-hole is lowered
Solution Approach 1:
The patent performs preliminary action by pre-forming concave portions with controlled volume distributions on the electronic component surfaces before forming the second insulation layer. This preliminary structure control ensures that when resin is applied, it distributes uniformly to create consistent second insulation layer thickness, which maintains reliable via-hole connections while providing adequate insulation coverage.
Data Source
AI summary
A wiring substrate includes a pad including an opening formed to penetrate the pad, a first insulation layer having a cavity to which the pad is exposed, an electronic component mounted on the pad exposed in the cavity, and a second insulation layer formed on the first insulation layer with covering the electronic component. The opening is formed so as to penetrate the pad which is exposed in the cavity. The electronic component is mounted on the pad so that the opening is exposed. An outermost layer of the electronic component includes a concave portion having a predetermined volume distribution. A position and a size of the opening are determined based on the predetermined volume distribution. The second insulation layer is provided in the concave portion, in a gap between a side surface of the electronic component and an inner wall surface of the cavity, and in the opening.