Ceramic Shielded Module Structure Without Solder Jetting
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Solution Overview
Problem
High-frequency modules experience solder jetting and undesirable solder ball formation during reflow soldering due to the melting and flow of solder between the Cu block and sealing resin, which compromises shielding effectiveness.
Innovation Solution
A module design featuring a ceramic wiring board with a ground conductor, conductive members between components, and a shield film that covers the sealing resin and wiring board, where the conductive members are formed by firing and electrically connected to the ground conductor and shield film, eliminating the need for solder and thus preventing solder jetting and ball formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solder is used to connect the Cu block to the mounted electrode, then electrical connectivity is achieved, but solder jetting and solder ball formation occur during reflow soldering
Solution Approach 1:
The patent extracts and removes the solder material from the connection structure between the Cu block and mounted electrode. By replacing solder with a conductive adhesive layer, the harmful solder jetting and ball formation during reflow soldering are eliminated while maintaining electrical connectivity through the adhesive layer.
Solution Approach 2:
The patent changes the material parameter of the connection layer from solder (metal) to conductive adhesive (polymer-based material). This parameter change allows the connection to withstand reflow soldering temperatures without melting, as the adhesive has a higher thermal stability and does not undergo phase change at soldering temperatures.
2Reliability
If a Cu block is used for shielding between components, then electromagnetic shielding effectiveness is improved, but solder jetting occurs during reflow soldering
Solution Approach 1:
The patent removes the solder material from around the Cu block by replacing it with conductive adhesive. This extraction eliminates the source of solder jetting while preserving the Cu block's shielding function, as the adhesive provides both mechanical bonding and electrical conductivity.
3Reliability
If solder is used to connect components on the wiring board, then electrical connectivity is achieved, but manufacturing complexity increases due to solder ball prevention measures
Solution Approach 1:
The patent extracts solder from the interconnection system and replaces it with conductive adhesive. This simplifies the manufacturing process by eliminating the need for complex solder ball prevention measures, reflow soldering control, and inspection procedures, while maintaining reliable electrical connectivity.
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 configuration ensures effective shielding between components without solder-related issues during reflow soldering, enhancing reliability and preventing solder balls, while maintaining electrical connectivity and reducing manufacturing costs.
Implementation Method 1
the conductive member is formed by firing simultaneously with the wiring board
Implementation Method 2
a shield film that covers an upper surface and a side surface of the sealing resin and a side surface of the wiring board. The shield film is electrically connected to the ground conductor, and the conductive member is electrically connected to the ground conductor and electrically connected to the shield film
Data Source
AI summary
A module includes: a wiring board as a ceramic board having a first main surface; a first component and a second component that are mounted on the first main surface; at least one conductive member disposed on the first main surface between the first component and the second component; a sealing resin that seals the first component, the second component, and the conductive member; and a shield film that covers an upper surface and a side surface of the sealing resin and a side surface of the wiring board. The shield film is electrically connected to a ground conductor. The conductive member is formed by firing simultaneously with the wiring board, and electrically connected to the ground conductor and electrically connected to the shield film.