Printed Wiring Board Support Plate Warpage Prevention
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Solution Overview
Problem
Existing printed wiring boards without core substrates tend to warp during semiconductor element mounting and are prone to short-circuit defects due to the lack of insulation between connection pads, especially when pads are arranged at fine pitches.
Innovation Solution
A printed wiring board design featuring a laminate with alternately laminated conductor and resin insulating layers, where via conductors are tapered and recessed, and a solder resist layer exposes conductor pads, supported by a support plate to prevent warpage and short-circuit defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a printed wiring board is designed without a core substrate to reduce complexity and cost, then device complexity is reduced, but the board becomes prone to warpage during semiconductor element mounting
Solution Approach 1:
The patent introduces a support plate as an intermediary element bonded to the back surface of the laminate. This support plate provides mechanical reinforcement and stability to prevent warpage during semiconductor element mounting, while allowing the front surface to maintain the simplified multi-layer structure without a core substrate. The support plate acts as a mediator that resolves the contradiction between structural simplicity and mechanical stability.
2Area of moving object
If connection pads are arranged at fine pitches to increase integration density, then area is reduced, but the board becomes prone to short-circuit defects due to lack of insulation
Solution Approach 1:
The patent applies local quality by forming resin insulating layers selectively between connection pads on the front surface of the laminate. These localized resin layers provide insulation precisely where needed between closely spaced pads, while allowing the pads themselves to maintain their fine pitch arrangement for high integration density. This resolves the contradiction by providing insulation only in the critical regions rather than requiring uniform spacing throughout the board.
3Ease of manufacture
If via conductors are made straight and flush with the surface to simplify manufacturing, then ease of manufacture is improved, but short-circuit defects increase due to insufficient insulation between adjacent pads
Solution Approach 1:
The patent forms resin insulating layers at specific locations between connection pads, providing localized insulation where short-circuit risks exist. This approach maintains manufacturing simplicity by not requiring complex via conductor geometries, while still achieving reliable insulation between closely spaced pads through the strategically placed resin layers.
Data Source
AI summary
A printed wiring board includes a support plate, a laminate formed on the support plate and including first conductor pads on first surface side of the laminate and first via conductors on second surface side of the laminate, and a solder resist layer interposed between the plate and the laminate and having openings formed such that the openings are exposing the first pads. The laminate has first surface on the first surface side and second surface on the second surface side on the opposite side and includes a first resin insulating layer forming the second surface of the laminate, and the first conductors are formed through the first insulating layer such that the first vias are tapering from the first surface side toward the second surface side of the laminate and have end surfaces recessed from the second surface of the laminate on the second surface side of the laminate.