Notched Strap Joint Structure for Chip-to-Lead Frame Alignment
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Solution Overview
Problem
Existing semiconductor devices using lead frames face challenges in achieving reliable electrical connections between the chip and the lead frame due to insufficient joint strength and alignment issues, leading to reduced yield and performance.
Innovation Solution
The semiconductor device incorporates a joint member with a notch portion on the joint surface, which enhances the joint strength and alignment by utilizing the surface tension of the joint material to cover the notch, preventing misalignment and ensuring a robust electrical connection between the gate electrode and the gate terminal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional joint structure is used to connect the chip to the lead frame, then the manufacturing process is simple, but the joint strength is insufficient and alignment precision is poor
Solution Approach 1:
The joint portion is designed with an asymmetric notch structure where one surface is positioned lower than the other, creating an uneven configuration. This asymmetric design provides better mechanical interlocking between the joint member and the lead frame, significantly improving joint strength while maintaining manufacturing simplicity
Solution Approach 2:
The invention transitions from a conventional planar joint surface to a multi-level joint structure with a notch portion creating different height levels. This dimensional change allows the joint member to engage with both the lower and upper surfaces, providing enhanced mechanical anchoring and alignment in multiple directions simultaneously
2Manufacturing precision
If a conventional joint structure is used to connect the chip to the lead frame, then the manufacturing process is simple, but the alignment precision is poor
Solution Approach 1:
The asymmetric notch configuration with one lower surface and one upper surface creates a unique geometric signature that guides the joint member into proper alignment. This asymmetric feature prevents misalignment by providing a single correct positioning orientation, thereby improving manufacturing precision without requiring complex alignment mechanisms
Solution Approach 2:
The notch portion is pre-formed on the joint portion before the joint member is applied. This preliminary structural preparation creates built-in alignment features that automatically guide the joint member into the correct position during assembly, eliminating the need for complex external alignment procedures
3Reliability
If the joint surface is flat and conventional, then the manufacturing process is simple, but the electrical connectivity reliability is reduced
Solution Approach 1:
The joint portion incorporates a vertical dimension with a notch creating lower and upper surfaces at different heights. This multi-level structure increases the effective contact area between the joint member and the joint portion, providing more pathways for electrical conduction and thereby enhancing electrical connectivity reliability
Solution Approach 2:
The joint structure combines multiple materials including the joint portion material, joint member material, and solder material in a composite configuration. This composite structure leverages the complementary properties of each material to achieve both mechanical strength and reliable electrical connectivity that single-material solutions cannot provide
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 notch design improves the yield and reliability of the semiconductor device by enhancing the joint strength and preventing misalignment, resulting in improved electrical connectivity and manufacturing efficiency.
Implementation Method 1
which enhances the joint strength and alignment by utilizing the surface tension of the joint material to cover the notch
Data Source
AI summary
According to one embodiment, a semiconductor device includes: a chip; a first electrode provided on the chip; a first connector provided above the first electrode, extending in a first direction, and provided with a joint portion to be joined to the first electrode, on an end portion in the first direction of the first connector; and a joint member for use in joint between the first electrode and the joint portion. The joint portion is provided with a notch portion on at least one end portion in the first direction of an upper surface of the joint portion. The joint member is in contact with the first electrode, a lower surface of the joint portion facing the first electrode, and at least part of the notch portion.