Lead Frame Wiring Structure with Leg Sections to Reduce Solder Rise
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Solution Overview
Problem
Conventional lead frame wiring structures for semiconductor modules experience stress concentration due to solder rising onto the horizontal lower face of bent sections, leading to potential breakage of semiconductor chips under heat deformation.
Innovation Solution
A lead frame wiring structure with a coupling part that includes leg sections extending from the coupling face section to the bonding parts, reducing the surface area of contact and thereby minimizing solder rise and stress concentration, by connecting these leg sections to the peripheral sections of the bonding parts between their end portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional L-shaped bent sections are used in lead frame wiring, then the wiring structure is simple and easy to manufacture, but solder rises onto the horizontal lower face causing stress concentration that breaks semiconductor chips
Solution Approach 1:
The bent section is divided into multiple segments: a first bent section extending upward from the horizontal lower face, and a second bent section extending horizontally from the first bent section. This segmentation prevents solder from rising directly onto the horizontal lower face while maintaining manufacturing simplicity
Solution Approach 2:
The bent section is extended into a third dimension by adding the first bent section that extends upward, transforming the conventional two-dimensional L-shaped structure into a three-dimensional configuration that blocks solder rise paths
2Area of stationary object
If solder rises onto the horizontal lower face of bent sections, then the bonding area increases, but stress concentration from heat deformation breaks semiconductor chips
Solution Approach 1:
The horizontal lower face is designed to be free from solder rise by positioning the first bent section to block the solder path, creating a localized quality difference where the bonding area maintains sufficient size while the critical horizontal lower face remains solder-free
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 reduces stress concentration on semiconductor chips, enhancing their reliability and longevity, particularly in high-temperature environments, such as in vehicle-mounted-motor drive control inverters.
Implementation Method 1
a first bonding part soldered to the semiconductor element, a second bonding part positioned spaced apart from the first bonding part and soldered to the object
Data Source
AI summary
A lead frame wiring structure including first and second bonding parts positioned apart from each other, and a coupling part extending in a first direction to couple the first and second bonding parts. The coupling part includes a coupling face section, and first and second leg sections extending respectively from two opposite end portions of the coupling face section toward the first and second bonding parts. The first bonding part includes a wide section having a side edge portion and a peripheral section adjacent to the side edge portion in a second direction, and a narrow section protruding in the first direction from the side edge portion. In the coupling part, the coupling face section is spaced apart from the two bonding parts in a third direction, and the first leg section is connected to the peripheral section of the first bonding part. The first to third directions are perpendicular to one another.