Wiring Substrate With Buried Linear Conductors
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Solution Overview
Problem
Existing wiring substrates face challenges in achieving narrow pitch through-wirings in ceramic substrates and require precise position adjustment during substrate burial, which complicates the manufacturing process and increases costs.
Innovation Solution
A wiring substrate design that incorporates a resin substrate with a buried substrate featuring densely packed linear conductors, eliminating the need for position adjustment by ensuring the gap between conductors is smaller than their diameter, and forming thicker wiring patterns to facilitate high-density vertical transmission paths without the need for precise alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If through-wirings are formed in a ceramic substrate, then vertical transmission paths are established, but pitch-narrowing is difficult to realize and position adjustment is required
Solution Approach 1:
The invention divides the substrate into two distinct parts: a core substrate (resin-based) and a buried substrate (ceramic-based with linear conductors). The buried substrate is segmented into multiple linear conductor rows that extend in the thickness direction, allowing each row to function independently without requiring precise alignment between substrates during assembly
Solution Approach 2:
The invention transitions from planar wiring to three-dimensional vertical transmission paths by forming linear conductors that penetrate through the buried substrate in the thickness direction. This dimensional change enables high-density wiring without requiring precise position adjustment in the lateral plane
2Productivity
If the gap between linear conductors is made smaller than the conductor diameter, then high-density vertical transmission paths are achieved, but manufacturing precision requirements increase
Solution Approach 1:
The linear conductors are pre-formed in the buried substrate before assembly with the core substrate. The conductors are created with predetermined spacing and dimensions, allowing the high-density pattern to be manufactured once during buried substrate fabrication rather than requiring precise positioning during final assembly
Solution Approach 2:
The invention changes the material parameter from traditional ceramic-only substrates to a composite structure with resin core substrate and ceramic buried substrate. This material parameter change enables the formation of linear conductors with gap smaller than diameter while maintaining manufacturing feasibility through the flexibility of the resin-based core substrate
3Productivity
If thicker wiring patterns are formed on the core substrate, then high-density vertical transmission paths are enabled, but the substrate becomes less flexible
Solution Approach 1:
The invention applies different material qualities to different parts of the substrate system: the core substrate uses flexible resin material with thicker wiring patterns for high-density connections where needed, while the buried substrate uses rigid ceramic material for stable linear conductor support. This local quality differentiation allows thick wiring patterns without compromising overall substrate flexibility
Data Source
AI summary
A wiring substrate includes a buried substrate disposed within a through-hole penetrating through a resin substrate of a core layer and including a plate-like body and a plurality of linear conductors penetrating the plate-like body, a first insulating layer covering a first surface of the resin substrate, a first wiring layer including a first pad pattern formed on a first surface of the buried substrate and a first wiring pattern formed on a first surface of the first insulating layer, and a third wiring pattern formed on the first surface of the resin substrate and covered by the first insulating layer. In the plurality of linear conductors, a gap between the adjacent linear conductors is smaller than a diameter of each of the linear conductors. The third wiring pattern is formed so as to have a thickness thicker than a thickness of the first wiring pattern.