Circuit Module Frame Deformation Mitigation via Electrode Displacement
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Solution Overview
Problem
Circuit modules face inward deformation of the frame-shaped board due to contraction stress from sealing resin curing, which is exacerbated by the mechanical mismatch between ceramic and resin materials, particularly in densely packed and miniaturized designs.
Innovation Solution
The center of each connection electrode on the frame-shaped board is inwardly displaced relative to the corresponding electrode on the plate-shaped board, allowing the curing contraction stress of conductive bonding materials to counteract the contraction stress of the sealing resin, thereby reducing deformation and enhancing connection reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sealing resin is filled and cured in the cavity, then the circuit components are protected and mechanical strength is improved, but the frame-shaped board deforms inwardly due to contraction stress
Solution Approach 1:
The connection electrodes on the frame-shaped board are positioned inwardly relative to the plate-shaped board before sealing resin curing. This preliminary positioning creates a geometric configuration that generates counteracting stress during resin curing, preventing the inward deformation caused by resin contraction stress.
Solution Approach 2:
The inward displacement of connection electrodes creates a counterbalancing mechanical stress that acts as a counterweight to the contraction stress of the sealing resin. This counter stress prevents the frame-shaped board from deforming inward during the curing process.
2Volume of moving object
If the width of the frame-shaped board is reduced for miniaturization, then the size of the circuit module is reduced, but the frame-shaped board becomes more susceptible to deformation
Solution Approach 1:
By pre-positioning the connection electrodes inwardly on the frame-shaped board, the design creates a built-in counteracting mechanism that compensates for the reduced structural rigidity caused by miniaturization. This preliminary geometric adjustment prevents deformation even in densely packed, miniaturized circuit modules.
3Ease of manufacture
If the connection electrodes are aligned centrally between the plate-shaped and frame-shaped boards, then the bonding is simplified, but the frame-shaped board deforms inwardly under sealing resin contraction stress
Solution Approach 1:
The connection electrodes on the frame-shaped board are intentionally positioned asymmetrically inwardly relative to the plate-shaped board, rather than being centrally aligned. This asymmetric positioning creates a mechanical counterbalance that prevents inward deformation during sealing resin curing, while still maintaining manufacturability.
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 effectively mitigates the contraction stress of the sealing resin, suppressing deformation of the frame-shaped board and improving the reliability of connections between the plate-shaped and frame-shaped boards, while maintaining mechanical strength and thermal cycle reliability.
Implementation Method 1
The connection electrodes on the plate-shaped board and the connection electrodes on the frame-shaped board are bonded together using conductive bonding materials, such as solder.
Implementation Method 2
When the sealing resin is filled in the cavity and then heat curing is performed, the resin contracts at a specific rate. This contraction stress is also exerted on the frame-shaped board
Data Source
AI summary
A circuit module includes connection electrodes on a plate-shaped board and connection electrodes on a frame-shaped board that are bonded together with conductive bonding materials there between. Circuit components are provided in portions of a surface of the plate-shaped board, the portions being located inward relative to the frame-shaped board. A sealing resin is filled and cured in a cavity, which is defined by the frame-shaped board and the plate-shaped board. Since the center of each of the connection electrodes on the frame-shaped board is inwardly displaced relative to the center of a corresponding one of the connection electrodes on the plate-shaped board by α, a curing contraction stress of the sealing resin is mitigated by a curing contraction stress of the conductive bonding materials. Thus, deformation of the frame-shaped board is suppressed.