Semiconductor Element Unit with Pre-Annealed Eutectic Bonding
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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, potentially damaging the circuit board.
Innovation Solution
The semiconductor element unit is designed with a first electrode having a flat surface roughness of less than or equal to 10 nm, forming eutectic bonding with the semiconductor element in a different part, and a semiconductor packaging circuit with a flat substrate surface, allowing for stable electrical connection without the need for post-mounting annealing, using a semiconductor element unit supply substrate with a flat substrate surface for stable transfer and connection.
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 contact surface smoothness deteriorates due to heat influence
Solution Approach 1:
The patent divides the electrode into two distinct functional regions: a bonding region that contacts the semiconductor element and undergoes eutectic bonding during annealing, and a mounting surface that remains separate from the annealing process to maintain smoothness. This segmentation allows the electrode to simultaneously achieve reliable electrical connection through bonding while preserving contact surface quality for subsequent mounting operations.
2Reliability
If annealing process is executed for semiconductor element and drive circuit board together, then eutectic bonding is formed, but drive circuit board may be damaged due to high temperature
Solution Approach 1:
The patent performs the annealing process to form eutectic bonding between the electrode and semiconductor element as a preliminary step before mounting the electrode onto the drive circuit board. By completing the bonding operation first and then separately mounting the electrode to the circuit board at lower temperatures, the harmful high-temperature effects on the circuit board are avoided while still achieving reliable electrical connection.
3Reliability
If electrode contact surface is exposed during annealing, then eutectic bonding can form, but contact surface smoothness deteriorates significantly
Solution Approach 1:
The patent applies different thermal treatments to different regions of the electrode structure. The bonding region is locally subjected to annealing to form eutectic bonding with the semiconductor element, while the mounting surface is protected from direct annealing exposure to maintain its smoothness. This local quality differentiation allows simultaneous achievement of bonding reliability and surface quality.
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 configuration enables excellent electrical connection between the semiconductor element and the circuit board, maintaining a smooth contact surface and avoiding damage to the drive circuit board, while allowing for efficient manufacturing and integration into semiconductor packaging circuits.
Implementation Method 1
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
AI summary
A method of manufacturing a semiconductor element unit, including: joining a semiconductor element to an electrode of a first substrate, the first substrate having a first sacrificial layer and the electrode formed on the first sacrificial layer; causing eutectic bonding between the semiconductor element and the electrode by an annealing process, after the semiconductor element is joined to the electrode, to form a semiconductor element unit; and separating the semiconductor element unit by removing the first sacrificial layer after the semiconductor element and the electrode are connected by eutectic bonding.