Multilayer PCB Adhesive Interface to Prevent Peeling and Cracking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing multilayer printed wiring boards face issues with peeling and stress between conductor layers and interlayer resin insulating layers, particularly when the number of conductor layers increases or the board size grows, leading to potential peeling and cracking.
Innovation Solution
A printed wiring board design featuring a smooth adhesive layer with protruding parts between the first conductor layer and resin insulating layer, ensuring strong adhesion and reducing stress, with a smooth upper and side surface on the conductor layer and a smooth film with protrusions on the adhesive layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple conductor layers and interlayer resin insulating layers are laminated to increase board capability, then the board can support more circuits and larger sizes, but peeling and cracking occur between layers due to stress
Solution Approach 1:
The adhesive layer is formed on the conductor layer before laminating the interlayer resin insulating layer, creating preliminary bonding that prevents peeling and cracking during subsequent manufacturing processes and usage. This preliminary action ensures reliable adhesion from the outset rather than attempting to fix adhesion issues after layer stacking.
Solution Approach 2:
The adhesive layer acts as an intermediary substance between the conductor layer and the interlayer resin insulating layer, mediating the bond between these two layers. This intermediary layer distributes stress and prevents direct contact between the conductor and resin, eliminating peeling and cracking at the interface.
2Adaptability or versatility
If the number of conductor layers increases to support more circuits, then circuit complexity and board functionality improve, but stress between layers increases causing peeling
Solution Approach 1:
The adhesive layer serves as a stress-distributing intermediary between conductor layers and interlayer resin insulating layers. When multiple layers are stacked to increase circuit complexity, the adhesive layer absorbs and distributes interlayer stress, preventing concentration of stress that would cause peeling and cracking.
Solution Approach 2:
The adhesive layer changes the physical and chemical parameters at the interface between conductor and resin layers, creating a transition zone with different mechanical properties. This parameter change allows the structure to accommodate thermal expansion differences and mechanical stress from multiple stacked layers without failing.
3Area of stationary object
If board size grows to accommodate more components, then functionality improves, but peeling and cracking occur due to increased stress
Solution Approach 1:
The adhesive layer is applied in advance to conductor layers before large-scale board assembly. This preliminary bonding action ensures that when the board grows to larger sizes with more components, the layers are already bonded and will expand together uniformly, preventing peeling and cracking that would occur with size increase.
4Ease of manufacture
If conventional lamination methods are used without adhesive layers, then manufacturing simplicity is maintained, but peeling and cracking occur between conductor layers and resin insulating layers
Solution Approach 1:
The adhesive layer is introduced as an intermediary substance that enables reliable bonding between conductor layers and interlayer resin insulating layers. While this adds a manufacturing step, it ensures proper adhesion without requiring complex lamination conditions, actually simplifying the overall manufacturing process by making bonding reliable and predictable.
Data Source
AI summary
A printed wiring board includes an insulating layer, a first conductor layer formed on the insulating layer, an adhesive layer formed on the first conductor layer, a resin insulating layer formed on the insulating layer such that the adhesive layer is formed between the first conductor layer and the resin insulating layer, and a second conductor layer formed on the resin insulating layer. The first conductor layer is formed such that the first conductor layer has a smooth upper surface and a smooth side surface and that the adhesive layer has a smooth film formed on the smooth upper and side surfaces, and a protruding part protruding from the smooth film.