Semiconductor Device Insulating Block Preventing Metal Migration
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Solution Overview
Problem
Semiconductor devices face reliability issues due to metal atom migration between wiring patterns, leading to short circuits, which is exacerbated by electric fields and can compromise their insulating properties and miniaturization efforts.
Innovation Solution
Incorporating an insulating block or groove portion between adjacent lead frames to increase the creepage distance, thereby preventing conduction paths from forming and enhancing the sealing capability of the semiconductor device, while maintaining miniaturization and insulating properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the distance between adjacent wiring patterns is reduced to achieve miniaturization, then the device size is reduced, but metal atom migration may form conduction paths causing short circuits
Solution Approach 1:
An insulating block is introduced as an intermediary structure between adjacent wiring patterns. This block physically separates the wiring patterns and increases the creepage distance, preventing metal atom migration from forming conduction paths while allowing the overall device size to remain compact.
Solution Approach 2:
The insulating block extends in the vertical dimension (thickness direction) between adjacent wiring patterns. By utilizing the vertical space rather than only horizontal spacing, the creepage distance is increased without proportionally increasing the device footprint, thus achieving miniaturization while maintaining reliability.
2Reliability
If the creepage distance between wiring patterns is increased to prevent short circuits, then reliability is improved, but the device size increases
Solution Approach 1:
The insulating block utilizes the vertical dimension (thickness direction) to increase the creepage distance. By extending the insulating block vertically between adjacent wiring patterns, the effective creepage path is lengthened without requiring proportional increases in horizontal spacing, thus preventing device size expansion.
Solution Approach 2:
The insulating block is strategically positioned only in specific regions where wiring patterns are adjacent and short circuit risk exists. This localized approach increases creepage distance precisely where needed without unnecessarily increasing the overall device volume in regions where insulation is already sufficient.
3Object-generated harmful factors
If metal atoms migrate on an insulator or at an interface due to electric field, then conduction paths form between adjacent wiring patterns, but the insulating properties deteriorate
Solution Approach 1:
The insulating block serves as a mediator that physically separates adjacent wiring patterns and their associated metal atoms. By increasing the creepage distance with the insulating block, the path for metal atom migration is lengthened and interrupted, preventing conduction path formation and preserving insulating properties even under electric field stress.
Data Source
AI summary
A semiconductor device includes a resin case which houses a semiconductor element, a plurality of lead frames disposed in the principal plane of a base of the resin case with spaces therebetween, and a block portion disposed over a space between adjacent lead frames along the adjacent lead frames. With the semiconductor device, the disposition of the block portion makes creepage distance long, compared with a case where the block portion is not disposed and therefore a space between the adjacent lead frames is flat. Accordingly, even if metal atoms contained in the lead frames or the like migrate on an insulator or at an interface because of migration, a conduction path is hardly formed between the adjacent lead frames. That is to say, a short circuit hardly occurs between the adjacent lead frames with the block portion therebetween. This semiconductor device provides improved reliability.