Terminal Electrode Structure to Prevent Metal Powder Scattering
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Solution Overview
Problem
Ultrasonic welding of a terminal electrode to a wiring pattern on an insulating substrate results in the scattering of fine metal powder, which lowers the reliability of semiconductor devices, particularly in power semiconductor applications due to potential dielectric breakdown from corona discharge.
Innovation Solution
A semiconductor device design featuring a terminal electrode with a bag-shaped internal space and a freestanding configuration achieved by injecting compressed air or pure water into the internal space to induce plastic deformation, filling the clearance with the wiring pattern and ensuring a stable connection without scattering fine metal powder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If ultrasonic welding is used to weld terminal electrode to wiring pattern, then welding connection is achieved, but fine metal powder scatters causing reliability reduction
Solution Approach 1:
The patent replaces the ultrasonic welding process with a mechanical pressing process. A pressing member applies pressure to deform the terminal electrode into the recess, creating an interference fit with the wiring pattern without generating friction or metal powder scattering. This substitution of welding mechanics with mechanical deformation mechanics resolves the contradiction by achieving strong connection without the harmful side effects of ultrasonic welding.
Solution Approach 2:
The patent introduces a recess structure as an intermediary element between the terminal electrode and wiring pattern. The recess acts as a mediator that guides the deformation of the terminal electrode and ensures proper engagement with the wiring pattern. This intermediary structure enables reliable mechanical connection without requiring ultrasonic welding, thus preventing metal powder scattering while maintaining connection strength.
2Reliability
If terminal electrode is deformed into recess to prevent metal powder scattering, then reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent segments the terminal electrode into distinct functional zones: a pressing portion that undergoes deformation, a welded portion that forms the connection, and a terminal portion that provides electrical contact. This segmentation allows each portion to be optimized for its specific function while simplifying the overall manufacturing process. The recess is also segmented with a bottom surface and side surface that guide the deformation process.
Solution Approach 2:
The recess structure is pre-formed in the insulating substrate before the terminal electrode is installed. This preliminary action prepares the receiving structure in advance, guiding the deformation and positioning of the terminal electrode during assembly. By preparing the recess beforehand, the patent simplifies the overall manufacturing process compared to forming the recess after electrode installation.
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
The solution prevents the scattering of fine metal powder, enhancing the reliability of semiconductor devices by maintaining a stable weld and reducing the risk of dielectric breakdown, especially in power semiconductor applications.
Implementation Method 1
injecting compressed air or pure water into the internal space to induce plastic deformation
Data Source
AI summary
According to the present disclosure, a semiconductor device comprises an insulating substrate having a wiring pattern in a surface layer thereof and a terminal electrode having a bag-shaped internal space with a terminal electrode tip aperture. The terminal electrode is grounded in a freestanding state by mating with the wiring pattern.