Three-Layer Wiring Substrate Profile for Fine-Pitch Adhesion
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Solution Overview
Problem
Existing wiring substrates face challenges in achieving high-density, fine-pitch wiring configurations due to limitations in adhesion between conductor layers and insulating layers, leading to potential wiring loss and signal transmission issues.
Innovation Solution
A wiring substrate design with a first build-up part having a minimum wiring width and inter-wiring distance smaller than a second build-up part, featuring a conductor pattern with a first metal layer, a second metal layer, and a third metal layer, where the width of each layer varies, improving adhesion and reducing wiring loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the wiring width and inter-wiring distance are reduced to achieve high-density configurations, then the quantity of wirings per unit area increases, but the adhesion between conductor layers and insulating layers deteriorates leading to wiring loss
Solution Approach 1:
The conductor layer is designed with non-uniform thickness, where the thickness varies in the width direction. Specifically, the thickness is greater at the edges compared to the center, creating local quality variations that enhance adhesion at critical interface regions while maintaining fine-pitch wiring capabilities in the overall structure.
Solution Approach 2:
The invention changes the thickness parameter of the conductor layer from a uniform value to a variable value across the width direction. This parameter variation is controlled such that the thickness gradient enhances the bonding interface between the conductor and insulating layers, thereby improving adhesion reliability without compromising the reduced wiring dimensions.
2Manufacturing precision
If the wiring width is reduced to achieve fine-pitch configurations, then the density of wiring increases, but the adhesion between conductor layers and insulating layers decreases causing wiring loss
Solution Approach 1:
The conductor layer exhibits local quality variation in thickness, with edges having greater thickness than the center. This local thickening at the edges creates enhanced adhesion zones that compensate for the reduced overall wiring dimensions, ensuring reliable bonding even when wiring width is precisely controlled at fine-pitch levels.
Solution Approach 2:
The conductor layer is formed as a composite structure with non-uniform thickness distribution, combining regions of different thickness within the same layer. This composite approach allows the layer to simultaneously achieve fine-pitch dimensions for high density while maintaining sufficient material volume at critical locations for adequate adhesion.
3Quantity of substance
If the inter-wiring distance is reduced to increase wiring density, then the quantity of wirings increases, but the adhesion between conductor layers and insulating layers deteriorates
Solution Approach 1:
By implementing non-uniform thickness distribution in the conductor layer with greater edge thickness, the invention creates localized adhesion enhancement zones that allow for reduced inter-wiring distances. The thickened edges provide sufficient bonding interface area even when the overall wiring density is increased through smaller spacing.
Data Source
AI summary
A wiring substrate includes a first build-up part including an insulating layer and a conductor layer, and a second build-up part including an insulating layer and a conductor layer. The minimum wiring width of wirings in the conductor layer of the first build-up part is smaller than the minimum wiring width of wirings in the conductor layer of the second build-up part. The minimum inter-wiring distance of the wirings in the first part is smaller than the minimum inter-wiring distance of the wirings in the second part. The first build-up part is formed such that the conductor layer includes a conductor pattern including a first metal layer, a second metal layer, and a third metal layer. The width of the first metal layer is larger than the width of the second metal layer. The width of the third metal layer is larger than the width of the first metal layer.