Semiconductor Clip Positioning With Cavity-Stud Alignment
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Solution Overview
Problem
Conventional clip attachment processes in semiconductor devices result in inaccurate clip positioning and undesired clip movement during handling and curing, leading to defective products due to clip displacement and excessive tilt.
Innovation Solution
Implementing complementary positioning formations, such as cavities and protrusions, between the electrically conductive clip and the semiconductor chip/pad, which engage to maintain precise clip positioning during soldering, using stud bumps for centering and controlling solder thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional clip attachment equipment is used to place clips on die and pad, then clip placement accuracy is initially adequate, but clip displacement occurs during handling and curing processes
Solution Approach 1:
The patent applies preliminary action by creating positioning formations (protrusions and cavities) on the clip and substrate before the soldering process. These formations are pre-configured to engage with each other, preventing clip displacement during subsequent handling and curing operations. The positioning formations are established in advance to counteract the instability that would otherwise occur during the soldering process.
2Reliability
If solder paste is used to connect clip to pad and die, then electrical coupling is achieved, but excessive clip tilt occurs due to solder thickness and clip floating
Solution Approach 1:
The patent introduces positioning formations (protrusions and cavities) as intermediary structures between the clip and substrate. These formations act as mediators that mechanically constrain the clip position during soldering, preventing the clip from floating or tilting excessively on the solder paste. The intermediary structures ensure proper alignment while the solder paste provides electrical coupling.
3Ease of manufacture
If clips are allowed to move freely during soldering, then soldering process is simple, but clip displacement leads to defective products
Solution Approach 1:
The patent applies segmentation by dividing the clip structure into functional parts: the main clip body for electrical coupling and positioning formations (protrusions/cavities) for mechanical constraint. This segmentation allows the soldering process to remain simple while the dedicated positioning formations prevent displacement. The separation of coupling function and positioning function resolves the contradiction between process simplicity and positioning accuracy.
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
Ensures accurate clip positioning and controlled solder thickness, preventing clip displacement and tilt, thereby reducing defects in the final semiconductor device.
Implementation Method 1
soldering the at least one electrically conductive clip in said bridge-like position to the at least one semiconductor chip and to the at least one electrically conductive pad to provide electrical coupling therebetween, wherein soldering is via soldering material at said coupling surfaces
Data Source
AI summary
A semiconductor device semiconductor chip mounted to a leadframe that includes an electrically conductive pad. An electrically conductive clip is arranged in a bridge-like position between the semiconductor chip and the electrically conductive pad. The electrically conductive clip is soldered to the semiconductor chip and to the electrically conductive pad via soldering material applied at coupling surfaces facing towards the semiconductor chip and the electrically conductive pad. The device further includes a pair of complementary positioning formations formed by a cavity in the electrically conductive clip and a protrusion (such as a stud bump or a stack of stud bumps) formed in the electrically conductive pad. The complementary positioning formations are mutually engaged to retain the electrically conductive clip in the bridge-like position to avoid displacement during soldering.