Electronic Module Assembly With Cured Adhesive for Reflow Stability
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Solution Overview
Problem
The issue of electronic modules falling during reflow soldering due to mechanical or electrical considerations, particularly when larger and heavier modules are installed on the first tin-side of a system board, is not adequately addressed by existing methods, leading to incomplete soldering and reliability issues.
Innovation Solution
An electronic module assembly structure that utilizes a height difference between a carrier and the soldering surfaces of leading pins to pre-dispense adhesive material, which cures during the reflow preheating process, ensuring a stable bond between the electronic module and the system board, even at high temperatures, using carriers like magnetic core components, resin blocks, and copper blocks to provide support at the geometric center.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the electronic module is installed on the first tin-side of the system board, then the power density and manufacturing process are improved, but the module may fall during the reflow soldering of the second tin-side due to gravity exceeding solder tension
Solution Approach 1:
The adhesive material is pre-applied to the carrier before the reflow soldering process. During the preheating phase of reflow, the adhesive cures and forms a strong bonding interface between the carrier and the system board, preventing module failure during subsequent high-temperature soldering operations
Solution Approach 2:
The adhesive material undergoes a parameter change from uncured state to cured state during the preheating phase of reflow soldering. This transformation occurs at a lower temperature than the solder melting point, allowing the adhesive to set before the module is subjected to high-temperature soldering conditions
2Reliability
If the reflow furnace parameters are adjusted to reduce heat on the first tin-side, then the module falling risk is reduced, but the soldering completeness and product reliability are affected
Solution Approach 1:
The adhesive material acts as an intermediary between the carrier and the system board, providing mechanical support and bonding strength during the reflow soldering process. This allows the module to remain stable without requiring reduced furnace temperatures, thereby maintaining complete soldering quality
3Reliability
If a protective cover is added to the carrier for heat insulation, then the module falling risk is reduced, but the device complexity and manufacturing cost increase
Solution Approach 1:
The carrier itself provides the bonding surface for the adhesive material, eliminating the need for additional protective covers or support structures. The adhesive material applied to the carrier's bottom surface creates a self-contained bonding solution that prevents module failure without adding external components
Solution Approach 2:
The adhesive bonding function is merged with the carrier structure by applying the adhesive directly to the carrier's bottom surface. This integration eliminates the need for separate protective covers or support structures, simplifying the overall assembly while maintaining reliability
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 solution enhances the reliability of the reflow soldering process, prevents module falling, simplifies assembly, and reduces manufacturing costs by ensuring a strong and heat-resistant bond without additional processing.
Implementation Method 1
the adhesive material between the carrier and the system board is completely cured into a solid state during the reflow preheating process
Implementation Method 2
the cured adhesive material is maintained in the stable state in the subsequent reflow soldering process at high temperature instead of being melted due to the high temperature of the reflow soldering process
Data Source
AI summary
The present disclosure is related to an electronic module assembly structure including a system board, an electronic module and an adhesive material. The system board includes a first upper surface and a first lower surface opposite to each other. The electronic module spatially corresponds to the first upper surface and includes plurality leading pins and a carrier. Each leading pin has a soldering surface and is connected to the first upper surface through a first reflow soldering process. When the plurality leading pins are connected to the first upper surface, a height difference is formed between the carrying surface of the carrier and the soldering surfaces. The adhesive material is disposed on the carrying surface or the first upper surface. The carrier is connected with the first upper surface through the adhesive material, so that the electronic module is fixed to the first upper surface through the adhesive material.