Semiconductor Electrode Layout for Eutectic Bonding and Smooth Contact
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Solution Overview
Problem
It is challenging to achieve reliable ohmic contact between semiconductor elements and electrodes while maintaining the smoothness of the electrode's contact surface, especially during the annealing process which can deteriorate the surface smoothness and potentially damage the drive circuit board.
Innovation Solution
A semiconductor element unit is designed with a first electrode having a flat mounting surface with surface roughness less than or equal to 10 nm, forming eutectic bonding with the semiconductor element in a different part. This configuration allows for excellent electrical connection without compromising the surface smoothness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If annealing process is executed to form eutectic bonding between electrode and semiconductor element, then electrical connection reliability is improved, but surface smoothness of electrode contact surface deteriorates
Solution Approach 1:
The electrode is divided into two distinct surfaces: a first surface that contacts the semiconductor element for eutectic bonding, and a second surface that contacts the drive circuit board. This segmentation allows the first surface to undergo annealing for reliable electrical connection while the second surface maintains its smoothness for optimal contact with the circuit board.
Solution Approach 2:
Different surfaces of the electrode are given different functional qualities. The first surface is designed to form eutectic bonding with the semiconductor element through annealing, while the second surface is maintained smooth for contact with the drive circuit board. This local differentiation of properties resolves the contradiction between needing heat treatment for bonding and maintaining surface smoothness.
2Reliability
If annealing process is executed while electrode is in contact with drive circuit board, then eutectic bonding is formed, but drive circuit board is damaged due to high temperature
Solution Approach 1:
The electrode is pre-configured with a specific structure before the annealing process, where the first surface is positioned to contact the semiconductor element while the second surface is oriented toward the drive circuit board. This preliminary arrangement allows selective heating of only the bonding interface during annealing, preventing thermal damage to the drive circuit board while still forming eutectic bonding.
Solution Approach 2:
The electrode structure enables localized heat application during annealing, where only the first surface in contact with the semiconductor element undergoes thermal processing for eutectic bonding, while the second surface contacting the drive circuit board remains thermally protected.
3Manufacturing precision
If electrode contact surface is made extremely smooth to ensure good contact with terminal part, then contact quality is improved, but eutectic bonding formation becomes difficult
Solution Approach 1:
The electrode is segmented into two surfaces with different functional requirements. The first surface is optimized for eutectic bonding with the semiconductor element, while the second surface is optimized for smooth contact with the drive circuit board terminal part. This segmentation allows each surface to be independently optimized for its specific function without compromise.
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
The solution enables excellent electrical connection between the semiconductor element and the circuit, maintaining a small-sized configuration while avoiding damage to the drive circuit board, and ensuring high manufacturing yield in semiconductor packaging circuits.
Implementation Method 1
forming eutectic bonding with the semiconductor element in a part different from the first electrode mounting surface
Implementation Method 2
it is possible to execute the so-called annealing process in which the electrode and the semiconductor element in contact with each other is placed in an environment at high temperature
Data Source
AI summary
A semiconductor element unit includes a semiconductor element; and a first electrode having a flat first electrode mounting surface whose surface roughness is less than or equal to 10 [nm] and forming eutectic bonding with the semiconductor element in a part different from the first electrode mounting surface. A semiconductor element unit supply substrate includes one or more semiconductor element units. A semiconductor packaging circuit includes the semiconductor element unit.