Embedded Wiring Board Metal Posts for Warpage and Contact
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Solution Overview
Problem
Existing printed wiring boards face challenges in ensuring reliable and consistent connections between electronic components and the board, particularly due to issues like warpage caused by thermal expansion differences and the risk of contact between adjacent wirings.
Innovation Solution
A printed wiring board design featuring a resin insulating layer with a first conductor layer embedded within, a second conductor layer projecting from the opposite side, metal posts on the connecting portions with a larger width than the wirings, and a solder resist layer exposing these metal posts, which are positioned side by side on every other adjacent wiring to prevent contact and enhance reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conductor layer is embedded into the resin insulating layer, then the connection reliability is improved, but the manufacturing complexity increases
Solution Approach 1:
The conductor layer is embedded into the resin insulating layer before the final board assembly, preparing the connection structure in advance. This preliminary embedding ensures reliable electrical connections are established before subsequent manufacturing steps, resolving the contradiction by prioritizing connection reliability while managing manufacturing complexity through staged processing.
2Strength
If metal posts with larger width than wirings are formed on connecting portions, then the connection strength is improved, but the manufacturing precision requirements increase
Solution Approach 1:
Metal posts with larger width than the wirings are formed specifically at the connecting portions where electronic components are mounted, while other wiring portions maintain their original dimensions. This localized enlargement of metal posts at critical connection points enhances connection strength without requiring uniform precision across the entire board, thereby resolving the contradiction between connection strength and manufacturing precision requirements.
3Ease of operation
If the solder resist layer has an opening structure exposing the metal posts, then the ease of component mounting is improved, but the manufacturing complexity increases
Solution Approach 1:
The solder resist layer is formed with opening structures that expose the metal posts before component mounting, preparing the mounting surface in advance. This preliminary opening structure allows components to be easily mounted by providing direct access to the metal posts, while the manufacturing complexity is managed by integrating this feature into the existing solder resist formation process.
4Area of stationary object
If connecting portions are positioned side by side on every other adjacent wiring, then the space utilization is improved, but the risk of contact between adjacent wirings increases
Solution Approach 1:
The solder resist layer acts as an intermediary that covers and isolates adjacent wirings while allowing controlled exposure at metal post locations. By positioning connecting portions side by side on every other adjacent wiring with the solder resist layer managing exposure, space utilization is improved while the intermediary solder resist prevents unwanted contact between adjacent wirings, resolving the contradiction between space utilization and reliability.
Data Source
AI summary
A printed wiring board includes an insulating layer, a first conductor layer embedded into first surface of the insulating layer and including multiple wirings such that the wirings include connecting portions positioned to connect an electronic component, respectively, a second conductor layer projecting from second surface of the insulating layer on the opposite side, a solder resist layer formed on the first surface of the insulating layer such that the solder resist layer is covering the first conductor layer and has an opening structure exposing the connecting portions of the wirings, and multiple metal posts formed on the connecting portions respectively such that each of the metal posts has a width which is larger than a width of a respective one of the wirings having the connecting portions. The wirings are formed such that the connecting portions are positioned side by side on every other adjacent one of the wirings.