Single Reflow Soldering for Power Integrated Modules
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Solution Overview
Problem
Power integrated modules (PIMs) require multiple reflow processes to solder power semiconductor dies and pin rings to copper traces, which is inefficient and may lead to unreliable electrical pathways.
Innovation Solution
A single reflow process is used to simultaneously solder semiconductor dies and hollow bush rings to copper traces on a direct bonded copper substrate, utilizing a guide plate with protrusions to align and secure the bush rings, which have specialized shapes for enhanced adhesion and conductivity, and then removing the protrusions after soldering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple reflow processes are used to solder dies and pin rings separately, then each component can be soldered individually, but the manufacturing time increases and the reliability of electrical pathways decreases
Solution Approach 1:
The patent combines the soldering of dies and pin rings into a single reflow process. The pin rings are positioned on the substrate before the dies, and both are simultaneously soldered to copper traces during one reflow cycle, eliminating the need for separate soldering operations and reducing manufacturing time while ensuring reliable electrical connections.
Solution Approach 2:
The pin rings are pre-positioned on the substrate at their final locations before the dies are attached. This preliminary placement ensures that when the single reflow process occurs, both components are already in their correct positions and will be soldered simultaneously, avoiding the need for multiple processing steps.
2Ease of manufacture
If multiple reflow processes are used, then separate soldering can be achieved, but the complexity of the manufacturing process increases
Solution Approach 1:
The manufacturing process is simplified by merging the soldering of dies and pin rings into a single reflow operation. This reduces the number of process steps, minimizes the complexity of manufacturing procedures, and makes the overall assembly process easier to control and execute.
3Manufacturing precision
If bush rings are deformed during mounting, then alignment may be improved, but the adhesion and conductivity of the solder joints deteriorate
Solution Approach 1:
The patent introduces a substrate as an intermediary platform that holds both the pin rings and dies in their correct positions before soldering. This substrate acts as a mediator that ensures proper alignment without requiring deformation of the bush rings, thereby maintaining both manufacturing precision and the reliability of solder joints.
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 method reduces the number of reflows required, enhances adhesion and conductivity between the solder joints and copper traces, and ensures reliable electrical pathways with minimal deformation of the bush rings, facilitating efficient assembly of power modules.
Implementation Method 1
attaching the bush rings and one or more dies to the copper traces by simultaneously reflowing said solder units and other solder units positioned between the dies and the copper traces
Data Source
AI summary
One illustrative method embodiment includes: providing a direct bonded copper (DBC) substrate including a plurality of copper traces; providing a guide plate having protrusions on a surface of the guide plate; mounting hollow bush rings onto the protrusions; mounting the bush rings onto the copper traces by aligning the protrusions of the guide plate with solder units on said copper traces; attaching the bush rings and one or more dies to the copper traces by simultaneously reflowing said solder units and other solder units positioned between the dies and the copper traces; and after said simultaneous reflow, removing the protrusions from the bush rings.