Bipolar Transistor Height Variations and Bump Bridging
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Solution Overview
Problem
The existing semiconductor devices with bipolar transistors on the same substrate face issues with poor electrical connection due to differences in emitter wiring heights, leading to inefficient mounting on external substrates.
Innovation Solution
The semiconductor device design features first and second bipolar transistors with distinct emitter layer heights, with a bump structure that spans both types, ensuring consistent electrical coupling and reduced connection issues during mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple bipolar transistors with different emitter wiring heights are formed on the same substrate, then device functionality is improved, but mounting reliability deteriorates due to poor electrical connection
Solution Approach 1:
The patent applies dimensionality change by forming a bump structure that extends in the vertical dimension (thickness direction) to bridge the height difference between emitter wirings of different bipolar transistors. This allows the single bump to connect to multiple emitter wirings at different heights, resolving the mounting reliability issue while preserving device functionality.
2Manufacturing precision
If emitter ballast resistor layers are added to equalize transistor characteristics, then current distribution is improved, but emitter wiring height differences and connection issues worsen
Solution Approach 1:
The patent resolves the contradiction by extending the connection structure into the vertical dimension through bump formation. The bump's thickness direction extension allows it to reach multiple emitter wirings at different heights, maintaining both current distribution uniformity (through ballast resistors) and electrical connection reliability.
3Device complexity
If a single bump is used to connect multiple transistors, then manufacturing complexity is reduced, but connection reliability worsens due to height variations
Solution Approach 1:
The patent maintains simple single-bump manufacturing by extending the bump in the vertical dimension. This thickness direction extension enables the single bump to naturally adapt to and connect with multiple emitter wirings at different heights without requiring complex multi-level bump structures.
Data Source
AI summary
A semiconductor device has a semiconductor substrate, and multiple first bipolar transistors on the first primary surface side of the semiconductor substrate. The first bipolar transistors have a first height between an emitter layer and an emitter electrode in the direction perpendicular to the first primary surface. The semiconductor device further has at least one second bipolar transistor on the first primary surface side of the semiconductor substrate. The second bipolar transistor have a second height, greater than the first height, between an emitter layer and an emitter electrode in the direction perpendicular to the first primary surface. Also, the semiconductor has a first bump stretching over the multiple first bipolar transistors and the at least one second bipolar transistor.