Semiconductor Element Unit With Flat Eutectic-Bonding Electrode
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Solution Overview
Problem
Existing semiconductor devices face challenges in achieving reliable electrical connection between the semiconductor element and the drive circuit board due to difficulties in forming ohmic contact and maintaining a smooth contact surface, which can be compromised by high-temperature annealing processes.
Innovation Solution
The semiconductor element unit is manufactured with a first electrode having an extremely flat surface that forms eutectic bonding with the semiconductor element, and the assembly is designed to maintain this flatness during high-temperature processing, allowing for stable electrical connection without additional annealing on the circuit board.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If annealing process is executed to form ohmic contact between electrode and semiconductor element, then electrical conductivity is improved, but smoothness of electrode contact surface deteriorates due to heat influence
Solution Approach 1:
The electrode contact surface is formed to be extremely smooth in advance, before the annealing process. This preliminary formation of the smooth surface allows the subsequent annealing to achieve ohmic contact without compromising the surface smoothness, as the smoothness is already established prior to heat treatment.
Solution Approach 2:
The process is segmented into distinct stages: first forming the smooth electrode surface, then performing annealing to create ohmic contact. This segmentation allows each process to be optimized independently - the surface formation process ensures smoothness while the annealing process ensures electrical conductivity, without one compromising the other.
2Reliability
If annealing process is executed while electrode is in contact with both semiconductor element and drive circuit board, then ohmic contact is formed, but drive circuit board may be damaged due to high temperature
Solution Approach 1:
The ohmic contact between the electrode and semiconductor element is formed in advance, before the electrode is mounted onto the drive circuit board. This preliminary formation of electrical connection allows the subsequent mounting process to occur at lower temperatures that will not damage the circuit board, while still achieving the required electrical conductivity.
Solution Approach 2:
The annealing process is performed beforehand to pre-establish the electrical connection, cushioning against the need for subsequent high-temperature processing after mounting. This prior cushioning protects the circuit board from heat damage while ensuring electrical conductivity is already established.
3Reliability
If electrode contact surface is made extremely smooth to ensure good contact with terminal part, then contact reliability is improved, but ability to form ohmic contact with semiconductor element becomes difficult
Solution Approach 1:
The smooth contact surface is formed in advance, before attempting to form ohmic contact. This preliminary preparation of the surface makes the subsequent ohmic contact formation easier, as the smooth surface facilitates uniform heating and contact during the annealing process, rather than creating manufacturing difficulties.
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
This method ensures excellent electrical conductivity between the semiconductor element and the drive circuit board while preventing damage to the circuit board, ensuring reliable and efficient electrical connection without the need for post-mounting annealing.
Implementation Method 1
the electrode and the semiconductor element in contact with each other is placed in an environment at high temperature (e.g., approximately 600 [°C]). When the annealing process is executed appropriately, the semiconductor element forms eutectic bonding with the electrode and reaches a state of the so-called ohmic contact
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 (e.g., approximately 600 [°C])
Data Source
Figure 1A~1B
Figure 2A~2D
Figure 3A~3E
AI summary
A semiconductor element unit (1, 201) includes a semiconductor element (2, 202); and a first electrode (3, 203) having a flat first electrode mounting surface (3B, 203B) whose surface roughness is less than or equal to 10 [nm] and forming eutectic bonding with the semiconductor element (2, 202) in a part different from the first electrode mounting surface (3B, 203B). A semiconductor element unit supply substrate (40, 240) includes one or more semiconductor element units (1, 201). A semiconductor packaging circuit (50, 250) includes the semiconductor element unit (1, 201).