Power Semiconductor Signal Terminal Vibration Suppression
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Solution Overview
Problem
In power semiconductor devices using wire bonding, the pad portion of the signal terminal experiences horizontal vibration due to ultrasonic signals, which is not effectively suppressed by existing resin-based terminal blocks, leading to potential joint failures.
Innovation Solution
The signal terminal design includes a joint portion with a distal end pad and a base portion, where the base portion has a thin section with a reduced vertical thickness and an upper surface covered by resin, ensuring the pad portion is securely held and reducing horizontal vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the pad portion is strongly held by the resin material to suppress horizontal vibration, then the holding force is improved, but the creepage distance for insulation between adjacent terminals is reduced
Solution Approach 1:
The resin material is selectively positioned to cover only the upper surface of the thin portion of the signal terminal, creating a localized holding region. This concentrated local support suppresses horizontal vibration of the pad portion while maintaining adequate creepage distance between adjacent terminals, as the resin does not extend laterally to interfere with insulation clearance.
Solution Approach 2:
The solution transitions from two-dimensional peripheral pressing (as in conventional technology) to three-dimensional vertical support by covering the upper surface of the thin portion. This dimensional change allows the resin material to provide holding force from above rather than from the sides, effectively suppressing horizontal vibration while preserving lateral insulation distance.
2Stability of the object's composition
If the entire periphery of the exposed surface is pressed with resin material to prevent floating, then the vertical stability is improved, but the horizontal vibration cannot be suppressed
Solution Approach 1:
Instead of uniformly pressing the entire periphery, the resin material is selectively applied to cover the upper surface of the thin portion. This localized approach provides horizontal vibration suppression at the critical thin portion region while maintaining vertical stability, addressing the specific weakness of conventional peripheral pressing.
3Stability of the object's composition
If a conical opening is formed to expose the pad portion and press it with resin, then the floating is prevented, but the horizontal vibration during ultrasonic bonding remains unsuppressed
Solution Approach 1:
The invention changes from peripheral horizontal pressing to vertical upper-surface covering. By positioning the resin material on the upper surface of the thin portion rather than pressing from the periphery, the solution effectively suppresses horizontal vibration during ultrasonic bonding while still preventing floating through the vertical support structure.
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 design enhances the holding force of the pad portion without altering the creepage distance for insulation, effectively suppressing vibration and preventing joint failures during wire bonding.
Implementation Method 1
the upper surface of the thin portion is covered with a resin material forming the terminal block... the vibration of the pad portion in a horizontal direction cannot be suppressed
Data Source
AI summary
Provided is a power semiconductor device including a signal terminal and a power semiconductor element. The power semiconductor element is arranged on a substrate. The signal terminal includes a main body portion and a joint portion, and a part of the signal terminal is held by a terminal block. The joint portion includes a distal end portion and a base portion. The distal end portion includes a pad portion that is exposed from the terminal block and connected to a signal line. The base portion includes a thin portion in which a thickness in a vertical direction is set to be smaller than that of the pad portion. The thin portion has an upper surface that is formed at a position lower than an upper surface of the pad portion and is covered with a resin material forming the terminal block.