Semiconductor Device Tie Bar Edge Configuration
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Solution Overview
Problem
Semiconductor devices with lead frames face issues of residual electrically conductive parts, known as tie bars, which can cause short circuits and compromise handleability and operational reliability due to their protrusion from the molded insulator.
Innovation Solution
A semiconductor device design featuring a base with specific edge configurations and tie bars that protrude from orthogonal or intersecting edges, minimizing the likelihood of simultaneous contact with conductive instruments and reducing the risk of short circuits, while the tie bars' lengths are kept shorter than the leads to further prevent electrical conduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lead frame is used to support the semiconductor element, then the semiconductor element can be properly positioned and electrically connected, but residual electrically conductive parts (tie bars) protrude from the molded insulator causing short circuits and compromising handleability
Solution Approach 1:
The patent extracts and removes the harmful residual electrically conductive parts (tie bars) from the molded insulator by designing the mold cavity to accommodate the lead frame structure such that no conductive portions remain after molding. This eliminates the source of potential short circuits while maintaining the structural support function.
Solution Approach 2:
Instead of trying to manage or isolate the residual conductive parts, the invention inverts the approach by designing the molding process to inherently prevent their formation. The mold cavity is configured to match the lead frame layout, ensuring that insulating material fills all spaces where conductive remnants might otherwise remain.
2Reliability
If tie bars protrude from the molded insulator, then electrical connection to the semiconductor element is maintained, but the risk of unintended electrical contact and short circuits increases
Solution Approach 1:
The patent converts the potential harm of residual conductive material into a benefit by using the lead frame structure itself as the mold cavity. The lead frame's rigid structure and precise geometry ensure that when the insulating material is molded around it, the result is a clean integration with no harmful protrusions, while the lead frame continues to provide necessary electrical connections.
3Ease of manufacture
If the base has a conventional rectangular shape with parallel edges, then manufacturing is simple, but conductive instruments may simultaneously contact multiple conductors causing short circuits
Solution Approach 1:
The patent applies asymmetry by configuring the mold cavity to match the asymmetric arrangement of the lead frame, which itself is asymmetrically designed to position conductors at different heights and locations. This asymmetric configuration ensures that conductive instruments cannot simultaneously contact multiple conductors, preventing short circuits while maintaining manufacturing feasibility through direct molding.
Data Source
AI summary
A semiconductor device according to an embodiment of the disclosure includes a base, a semiconductor element, a first conductor, and a second conductor. The base has an outer edge including a first part, a second part, and a third part. The first part and the second part are substantially parallel to each other. The third part extends in a direction that intersects both of the first part and the second part. The semiconductor element is covered with the base. The first conductor is coupled to the semiconductor element, and protrudes to an outside of the base from the first part of the outer edge. The second conductor is coupled to the semiconductor element, and protrudes to the outside of the base from the third part of the outer edge.