Leadframe Die-Pad Support Arm for Semiconductor Packaging
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Solution Overview
Problem
The existing semiconductor packaging technologies face challenges in supporting larger semiconductor dies within the restricted area and layout rules, leading to instability during wirebonding and packaging processes due to the limited size of traditional die-pads and lead-pads.
Innovation Solution
A leadframe design with a die-pad having a base portion and an upper portion extending laterally, supported by a removable support arm that extends beyond the package dimensions, providing additional stability during packaging and later removed to comply with design rules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a larger semiconductor die is used, then the die area increases, but the die-pad area is restricted by design rules
Solution Approach 1:
The die-pad is designed with a two-level structure: a base portion resting on the assembly surface and an upper portion extending vertically above the base portion. This vertical extension into the third dimension allows the die-pad to support a larger semiconductor die area while the footprint on the assembly surface remains within design rule restrictions. The upper portion provides additional die mounting surface area without increasing the planar area occupied on the circuit board.
2Area of moving object
If the die-pad area is increased to support larger dies, then the die mounting area increases, but the stability during wirebonding deteriorates due to extended leadframe structure
Solution Approach 1:
The leadframe structure is segmented into distinct functional portions: a base portion that provides stability and rests on the assembly surface, and an upper portion that extends vertically to provide additional die mounting area. This segmentation allows each portion to optimize its function - the base portion maintains stability during wirebonding while the upper portion enables larger die support.
3Stability of the object's composition
If a support structure is added to stabilize the die-pad, then the stability during packaging improves, but the device complexity increases
Solution Approach 1:
The support structure is merged with the die-pad itself, forming an integrated two-level structure where the base portion and upper portion are part of the same die-pad component. This eliminates the need for separate support elements and reduces overall device complexity while maintaining the stability benefits during packaging and wirebonding processes.
Data Source
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AI summary
In one embodiment, a method is provided for packaging a semiconductor die. A leadframe having a die-pad and one or more lead-pads is placed (502) on an assembly surface. The die-pad has a base portion (202) resting on the assembly surface, an upper portion (204) on the base portion extending laterally from the base portion, and a support arm (208) extending from and supporting the upper portion of die-pad. A semiconductor die (206) is wirebonded (504) to a top surface of the upper portion of the die-pad. The semiconductor die is wirebonded (506) to the one or more lead-pads (210). The semiconductor die and leadframe are encased (508) in a package material (802). The package material fills a space between the upper portion of the die-pad and the assembly surface. A portion of the support arm located in a cutting lane is removed (512).