Semiconductor Module Lead Contour for Solder Shift Prevention
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Solution Overview
Problem
The existing methods for bonding conductive members on a circuit board to leads using plate-shaped solder often result in bonding failures due to positional shifts during the reflow process, leading to reduced insulation properties and manufacturing inefficiencies.
Innovation Solution
A semiconductor module design featuring leads with a specific contour shape, where the bonding portion has a larger width dimension that changes to a smaller dimension near the coupling portion, and a corresponding jig configuration that restricts the movement of plate-shaped solder, ensuring accurate positioning and bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a jig with an opening is used to dispose plate-shaped solder and the conductor plate is detached after bonding, then the conductor plate can be removed from the bonding area, but the position of the plate-shaped solder may shift to the coupling portion during the reflow process
Solution Approach 1:
The lead is divided into distinct functional portions: a bonding portion for solder attachment and a coupling portion for electrical connection. The bonding portion has a larger width that transitions to a smaller width at the coupling portion, creating a natural boundary that prevents solder migration while allowing jig detachment.
Solution Approach 2:
The bonding portion acts as an intermediary structure between the coupling portion and the solder. Its enlarged width provides a stable platform for solder placement that is protected from shifting by the width reduction at the coupling portion, while still allowing the jig to be removed.
2Manufacturing precision
If the contour of the bonding portion is designed with displaced end portions and reduced width near the coupling portion, then positional shift of solder is prevented, but the lead structure becomes more complex
Solution Approach 1:
The lead structure maintains a simple overall form but introduces localized geometric features at the bonding portion. The end portions are displaced in opposite directions and the width is reduced near the coupling portion, creating local constraints that prevent solder shifting without complicating the entire lead structure.
3Productivity
If plate-shaped solder is used for bonding conductive members and leads, then efficient electrical connection is achieved, but bonding failures occur due to positional shifts during reflow
Solution Approach 1:
The lead is pre-formed with a bonding portion that has a specific contour shape with displaced end portions and reduced width near the coupling portion. This preliminary geometric configuration creates physical constraints that prevent solder from shifting during the reflow process, ensuring bonding reliability while maintaining the efficiency of plate-shaped solder bonding.
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 approach reduces bonding failures and maintains insulation properties by preventing positional shifts of the solder during the bonding process, enhancing manufacturing yield and reducing costs.
Implementation Method 1
heating and melting the plate-shaped bonding material
Implementation Method 2
bonding the bonding portion of a lead to a conductive member on a circuit board to each other via a bonding material
Data Source
AI summary
A semiconductor module includes a lead including a first bonding portion and a coupling portion extending in a Y direction from the first bonding portion. The first bonding portion has a first width end, and a second width end connected to the coupling portion. The lead has first and second length sides opposite to each other in an X direction. The lead has in the X direction first and second widths at first and second positions, and the second position is away from the first position in the Y direction. In the plan view, the lead has a shape in which the first width is greater than the second width such that positions of the first and second length sides at the second position are respectively located inward in the X direction with respect to positions of the first and second length sides at the first position.