Semiconductor Bonding Structure for Stable Solder Thickness
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Solution Overview
Problem
The use of Ni balls in semiconductor devices is limited, as they melt in solder melting furnaces, potentially failing to ensure the minimum solder thickness, leading to reliability issues.
Innovation Solution
A semiconductor device design featuring a semiconductor element with main electrodes on both surfaces, a bonding member, and wire pieces protruding from the first facing surface, ensuring the thickness of the bonding member even with warped elements, and allowing solder to spread without obstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If Ni balls are used to ensure solder thickness, then the minimum solder thickness can be ensured, but the Ni balls melt in solder melting furnaces leading to reliability issues
Solution Approach 1:
The patent extracts the thickness assurance function from the Ni ball material itself and transfers it to the geometric structure of spherical protrusions. The spherical shape maintains the thickness assurance capability while eliminating the material reliability issue by using solder-compatible materials.
Solution Approach 2:
The patent changes the material parameter of the thickness assurance element from Ni (nickel) to solder-compatible materials, while maintaining the functional parameter of thickness assurance through the spherical geometric structure. This parameter change resolves the contradiction between manufacturing precision and reliability.
2Manufacturing precision
If wire pieces are added to ensure bonding member thickness, then the bonding member thickness is ensured, but the device complexity increases
Solution Approach 1:
The patent merges the thickness assurance function with the existing spherical protrusion structure in the bonding member. By integrating the thickness assurance feature into the bonding member's geometry rather than adding separate components, the solution maintains manufacturing precision while minimizing device complexity.
Solution Approach 2:
The spherical protrusions in the bonding member serve multiple functions: they provide mechanical support, ensure minimum bonding member thickness, and facilitate proper solder spread. This multi-functionality reduces the need for additional components, thereby limiting the increase in device complexity.
Data Source
AI summary
In a semiconductor device, a semiconductor element has a front electrode and a back electrode. The back electrode is connected to a wiring member through a bonding member. Wire pieces are disposed in the bonding member, and bonded to a bonding surface of the wiring member to protrude toward the semiconductor element. The bonding member has, in a plan view, a central region that overlaps with a central portion of the semiconductor element including an element center, and an outer peripheral region that includes a portion overlapping with an outer peripheral portion of the semiconductor element surrounding the central portion and surrounds the central region. At least four wire pieces are disposed in the outer peripheral region at positions corresponding to at least four respective corners of the semiconductor element. At least one wire piece is disposed to extend toward the element center in the plan view.