Coreless Wiring Substrate Adhesion via Dual-Cure Resin Segmentation
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Solution Overview
Problem
The manufacturing of coreless type wiring substrates faces challenges in achieving sufficient adhesion of wiring layers due to the firm curing of the lowermost resin layer, which prevents adequate roughening of the surface, and difficulties in forming fine wiring layers on both sides using wet etching methods.
Innovation Solution
A method involving the formation of an etching stop layer, multiple wiring and insulating layers, and strategic via hole creation to ensure proper adhesion and surface roughening, allowing for the removal of the supporting member and subsequent formation of connected wiring layers with improved adhesion and fine pitch capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the lowermost resin layer is firmly cured through heating, then the structural stability is improved, but the surface roughening capability deteriorates
Solution Approach 1:
The patent divides the resin layer structure into two distinct parts: a firmly cured lowermost resin layer providing structural stability, and an uncured or lightly cured upper resin layer providing surface roughening capability. This segmentation allows each layer to fulfill its specific function without compromising the other.
Solution Approach 2:
The patent applies different curing degrees to different regions of the resin layer. The lowermost resin layer is firmly cured for stability, while the upper resin layer remains uncured or lightly cured to maintain surface roughness. This local quality differentiation resolves the contradiction between structural stability and surface roughening capability.
2Strength
If wet etching is performed on thick copper foil and thick metal plating layer, then the adhesion strength is improved, but the wiring layer fineness deteriorates
Solution Approach 1:
The patent changes the thickness parameters of the copper foil and metal plating layer to thin dimensions. This parameter change allows the use of etching methods that can achieve both sufficient adhesion strength and fine wiring layer precision, resolving the contradiction between adhesion strength and wiring layer fineness.
3Adaptability or versatility
If the supporting member is removed to create coreless structure, then the substrate flexibility is improved, but the wiring layer adhesion deteriorates
Solution Approach 1:
The patent performs preliminary actions by forming the etching stop layer and carefully controlling the removal process of the supporting member. This preliminary action ensures that the resin layers maintain their structural integrity and surface properties, preventing adhesion deterioration when the supporting member is removed.
Solution Approach 2:
The patent applies different properties to different parts of the resin layer structure. The lowermost resin layer is firmly cured to maintain structural stability after supporting member removal, while the upper resin layer is kept uncured or lightly cured to provide good adhesion for wiring layers. This local quality differentiation resolves the contradiction between substrate flexibility and wiring layer adhesion.
Data Source
AI summary
A method of manufacturing a wiring substrate, includes, forming an etching stop layer and a first wiring layer on a supporting member, forming a first insulating layer on the first wiring layer, forming a via hole reaching the first wiring layer, and forming the wiring layers of an n-layer and the insulating layers of an n-layer, removing the supporting member and the etching stop layer, thereby forming a build-up intermediate body, forming a second insulating layer on the wiring layer of an n-th layer, and forming a third insulating layer on first wiring layer, forming a via hole reaching the wiring layer of the n-th layer, and forming a via hole reaching the first wiring layer, forming a roughened face to the third insulating layer, and forming a second wiring layer connected to the wiring layer, and forming a third wiring layer connected to the first wiring layer.