Columnar Conductor Wiring Board with Insulating Support
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Solution Overview
Problem
Existing wiring boards with projection electrodes face issues of disconnection and cracking when mounted on motherboards due to thermal expansion and resin curing shrinkage, leading to unreliable mounting and potential separation of semiconductor devices.
Innovation Solution
A wiring board with columnar conductors and an insulating support portion that expands from the conductor tips towards the board, reducing stress and resin usage, and made from sintered metal fired simultaneously with ceramic layers, to enhance mountability and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the projection electrode is embedded in the resin layer with the upper end surface substantially flush with the upper surface of the resin layer, then the multilayer ceramic board can be mounted on the motherboard, but the motherboard may push the resin layer upward when distorted by thermal expansion, causing disconnection or cracking
Solution Approach 1:
The patent applies beforehand cushioning by providing a protruding portion that extends beyond the resin layer surface. This protruding portion acts as a preventive measure against the harmful effect of motherboard distortion, cushioning the stress before it can cause disconnection or cracking of the ceramic board. The protruding portion is positioned to make contact with the motherboard first, absorbing the pushing force from thermal expansion distortion.
2Reliability
If the semiconductor device and multilayer ceramic board are substantially entirely sealed with resin, then the semiconductor device is protected, but the curing shrinkage of the resin layer increases, causing warping and making mounting difficult
Solution Approach 1:
The patent applies the taking out principle by extracting the protruding portion from the resin layer. Instead of completely sealing the semiconductor device with resin, the protruding portion is left exposed beyond the resin surface. This extraction reduces the amount of resin required, thereby reducing curing shrinkage and preventing board warping, while still providing adequate protection to the semiconductor device.
3Manufacturing precision
If a shrinkage suppressing sheet is used to create the projection electrode, then the projection electrode can be formed with controlled dimensions, but the sheet must be precisely positioned and the firing process must be carefully controlled
Solution Approach 1:
The patent applies merging by combining the projection electrode formation with the ceramic board firing process. The green sheet containing the projection electrode pattern is laminated together with the ceramic green sheets, and both are fired simultaneously in one process. This merging eliminates the need for separate precise positioning and firing control of the shrinkage suppressing sheet, simplifying the manufacturing process while maintaining dimensional control.
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
The solution provides improved reliability by reducing stress from thermal expansion, preventing disconnection and cracking, and minimizing resin curing shrinkage, resulting in stable and efficient mounting on motherboards.
Implementation Method 1
made from sintered metal fired simultaneously with ceramic layers
Implementation Method 2
reducing stress from thermal expansion
Implementation Method 3
the curing shrinkage of the resin layer may be increased, and the multilayer ceramic board may be warped
Data Source
AI summary
A wiring board with a columnar conductor includes a wiring board defined by a multilayer ceramic board, a columnar conductor on an upper surface of the wiring board, and an insulating support portion arranged to support a side of the columnar conductor and having an external shape that expands from a tip of the columnar conductor toward the wiring board.