Multilayer Circuit Board Opening Layout for Thermal Bonding Reliability
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Solution Overview
Problem
The connection portions of circuit boards with thermoplastic resin layers are prone to unintended deformation and peeling due to thermal history, which affects the reliability of the multilayer body and interfaces between insulator layers and conductors.
Innovation Solution
A circuit board structure with a multilayer body featuring larger opening holes in the connection portion compared to the circuit portion, allowing controlled deformation and venting of gases during thermal bonding, thereby reducing peeling and deformation risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If connection portions are joined to external boards via conductive joint material through thermal processing, then reliable electrical connection is achieved, but unintended deformation and peeling of conductors occur due to excessive thermal history
Solution Approach 1:
The patent applies local quality by creating distinct opening hole ratios in different regions: the connection portion has a larger opening hole ratio (higher venting capability) compared to the circuit portion. This local differentiation allows the connection area to release thermal stress and gases more effectively during joining processes, preventing deformation and peeling while maintaining reliable electrical connections.
2Strength
If thermoplastic resin layers are laminated and thermally pressure-bonded to form multilayer body, then structural integrity is achieved, but connection portions undergo unintended deformation due to accumulated thermal history
Solution Approach 1:
The patent implements local quality by differentiating the opening hole ratios between the connection portion and circuit portion. The connection portion's larger opening holes provide localized stress relief during thermal processing, preventing shape deformation in critical connection areas while maintaining the overall structural integrity of the multilayer body through controlled gas release and thermal stress management.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design effectively reduces unintended deformation and peeling of conductors, improves electromagnetic shielding, and ensures reliable connections by managing thermal history and gas release in the connection area.
Implementation Method 1
a connection portion joined to an external board via a conductive joint material
Implementation Method 2
insulating layers made of thermoplastic resin are laminated and thermally pressure-bonded to each other
Implementation Method 3
thermally pressure-bonded to each other to form the first transmission line and the second transmission line
Implementation Method 4
the connection portions of the first transmission line and the second transmission line are connected to each other by performing processing such as locally heating the connection portions
Data Source
AI summary
A circuit board includes a multilayer body including a main surface, a mounted conductor, and a signal conductor at an intermediate position in the lamination direction of the multilayer body, and a ground conductor on the main surface. The multilayer body includes a connection portion including a portion overlapping the mounted conductor and overlapping an external board joined via a conductive joint material through use of the mounted conductor, and a circuit portion. A first region, which is the region of a circuit portion of the ground conductor, includes opening holes and a second region, which is the region of a connection portion of the ground conductor, includes opening holes. The ratio of the opening area of the opening holes to that of the second region is larger than the ratio of the opening area of the opening holes to that of the first region.