Coreless PCB High-Rigidity Layer Warpage Control
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Solution Overview
Problem
Coreless printed circuit boards face challenges in achieving sufficient rigidity, leading to deformation issues like warpage and twisting during manufacturing, as they lack the structural support provided by a core board.
Innovation Solution
Incorporating a high-rigidity layer with a material such as glass or metal, along with a resin insulating layer and via structures that connect circuit layers, to enhance mechanical strength and resist deformation, while also using insulating members to prevent adhesion issues and crack formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a coreless board structure is used to achieve miniaturization and high density integration, then the board thickness is reduced and integration density is improved, but the mechanical strength and rigidity deteriorate, leading to warpage and twisting during manufacturing
Solution Approach 1:
The patent introduces a high-rigidity layer made of glass or metal composite materials between circuit layers to provide mechanical strength while maintaining the coreless thin-board structure. This composite layer resolves the contradiction by combining the benefits of thin design with enhanced rigidity through material composition.
Solution Approach 2:
Instead of making the entire board thick to improve strength, the patent applies a localized high-rigidity layer only where structural support is needed. This allows different regions of the board to have different properties - thin and flexible where needed, and rigid where structural support is required - thus resolving the contradiction between overall thickness and localized strength.
2Volume of moving object
If a coreless board structure is used to achieve miniaturization and high density integration, then the board thickness is reduced and integration density is improved, but the board stability deteriorates, leading to warpage and twisting during manufacturing
Solution Approach 1:
The high-rigidity glass or metal layer provides dimensional stability and prevents warpage during manufacturing processes. This composite structure maintains board stability while keeping the overall board thin, resolving the contradiction between reduced thickness and maintained stability.
Solution Approach 2:
The high-rigidity layer is strategically positioned between circuit layers where stability is most needed during manufacturing, allowing the board to remain thin overall while having localized regions of enhanced stability to prevent warpage and twisting.
3Area of moving object
If via structures with decreased diameter are used to connect circuit layers, then the high density integration is improved, but the manufacturing precision requirements increase due to tighter tolerances
Solution Approach 1:
The high-rigidity layer provides a stable substrate that maintains via hole alignment and shape during drilling and plating processes. This stability allows for tighter via spacing with acceptable manufacturing tolerances, resolving the contradiction between high density and precision requirements.
Solution Approach 2:
The patent changes the material parameter of the intermediate layer to high-rigidity glass or metal, which alters the mechanical properties during via formation. This parameter change enables tighter via spacing while maintaining manufacturing feasibility through improved hole wall stability and reduced deformation.
Data Source
AI summary
A printed circuit board may include: a first circuit layer; a first insulating layer disposed on the first circuit layer; a high-rigidity layer disposed on the first insulating layer; and a second circuit layer disposed on the high-rigidity layer and connected to the first circuit layer by a first via extending through the first insulating layer and the high-rigidity layer, wherein a rigidity of the high-rigidity layer is greater than a rigidity of the first insulating layer.