Power Semiconductor Module Bonding Wire Lead Frame Rigidity
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Solution Overview
Problem
The existing power semiconductor module design faces challenges in achieving sufficient bonding strength between the bonding wire and the branch lead frame due to the low rigidity of the branch lead frame, which limits the application of vibration energy during bonding.
Innovation Solution
The power semiconductor module incorporates a control lead frame with a first lead frame portion and a second lead frame portion connected via a bent portion, where the bonding wires are connected to the control electrodes of semiconductor devices, allowing for increased vibration energy application in the longitudinal direction of the lead frames, enhancing bonding strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If radio frequency vibration is applied to bond the bonding wire to the branch lead frame portion, then bonding is achieved, but the low rigidity of the branch lead frame portion causes it to vibrate together with the bonding wire, preventing sufficient vibration energy from being applied to the bonding wire and lead frame portion
Solution Approach 1:
The patent changes the bonding direction from the transverse direction (perpendicular to the lead frame extension) to the longitudinal direction (along the lead frame extension). By orienting the bonding wire end portion to extend in the longitudinal direction of the lead frame and applying vibration in this direction, the lead frame's inherent rigidity in the longitudinal direction is utilized to prevent unwanted vibrations, thereby enabling sufficient vibration energy to be applied to the bonding wire for strong bonding.
2Use of energy by moving object
If the bonding wire end portion is disposed on the distal end side of the branch lead frame portion and vibrated perpendicular to the lead frame extension, then bonding can be performed, but large vibration energy cannot be given to the bonding wire and lead frame portion
Solution Approach 1:
The patent reorients the bonding configuration from transverse bonding (perpendicular to lead frame extension) to longitudinal bonding (parallel to lead frame extension). The bonding wire end portion is made to extend in the longitudinal direction of the lead frame, and vibration is applied in this longitudinal direction. This dimensional change allows the lead frame's structural rigidity to support and transmit vibration energy effectively, enabling large vibration energy to be applied to achieve strong bonding.
Solution Approach 2:
The patent changes the direction parameter of vibration application from transverse to longitudinal relative to the lead frame extension. This parameter change aligns the vibration direction with the lead frame's stiffest axis, maximizing the transmission of vibration energy to the bonding wire and preventing energy loss due to unwanted lead frame vibrations.
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 improves the bonding strength between the bonding wire and the lead frame, enabling more effective energy transfer and reducing resonance issues between semiconductor devices connected in parallel.
Implementation Method 1
radio frequency vibration is applied in a state where the bonding wire is pressed against the lead frame, and vibration energy is applied to the bonding wire to bond by frictional heat generated between the bonding wire and the lead frame
Implementation Method 2
vibration energy is applied to the bonding wire to bond by frictional heat generated between the bonding wire and the lead frame
Data Source
AI summary
The present invention is directed to improving the bonding strength between a bonding wire and a lead frame bonded to a plurality of semiconductor devices electrically connected in parallel. One end and the other end of a first bonding wire are connected to a control electrode and a first lead frame portion or a bent portion of a first semiconductor device, and one end and the other end of a second bonding wire are connected to a control electrode and a second lead frame portion of a second semiconductor device. The first lead frame portion extends in a direction overlapping with the first semiconductor device from the bent portion toward the side opposite to the first semiconductor device side, and the second lead frame portion extends from the bent portion toward the second semiconductor device side in a direction overlapping with the second semiconductor device.