Semiconductor Contact Redistribution Using Oblong Conductors
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Solution Overview
Problem
Semiconductor device packaging faces challenges in reducing overall size while increasing the number of external connections, as existing techniques struggle to balance the spacing and dimensions of internal and external contacts, particularly with the use of redistribution layers, which often require tight manufacturing tolerances and higher costs.
Innovation Solution
The implementation of conductors with oblong cross-sections that extend laterally beyond internal electrical contact elements, allowing for increased spacing and dimensions of connections with redistribution interconnectors without additional layers, while maintaining reduced internal contact element spacing, using pre-fabricated redistribution layers with less stringent manufacturing tolerances and cost-effective lamination techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If redistribution layers are used to fan out die contacts to external contacts, then the area for external contacts is increased and spacing is improved, but manufacturing precision requirements increase and costs increase
Solution Approach 1:
The patent applies preliminary action by pre-forming conductors with oblong cross-sections on the die before packaging. These conductors are prepared in advance with enlarged ends that will later align with redistribution layer interconnectors, eliminating the need for precise alignment during assembly and reducing manufacturing precision requirements.
Solution Approach 2:
The patent changes the geometric parameters of the conductors by forming them with oblong cross-sections having enlarged ends. This parameter change allows the conductors to accommodate misalignment and reduces the precision required for positioning, while still achieving reliable electrical connections to the redistribution layer interconnectors.
2Volume of moving object
If internal contact elements are spaced closer together to reduce device size, then device size is reduced, but the spacing and dimensions of connections with redistribution interconnectors become more difficult to achieve
Solution Approach 1:
The patent applies local quality by creating conductors with non-uniform cross-sections - the oblong shape with enlarged ends at specific locations. This local enlargement at the connection points allows for easier alignment with redistribution interconnectors even when internal contact elements are closely spaced, while maintaining compact overall device dimensions.
Solution Approach 2:
The conductors are pre-formed with their oblong cross-sections and enlarged ends before the die is packaged and connected to the redistribution layer. This preliminary preparation of the conductor geometry ensures that even with tight spacing, the connection interfaces are optimized for alignment and connection reliability.
3Ease of manufacture
If pre-fabricated redistribution layers are used instead of built-up layers, then manufacturing cost is reduced and tolerances are less stringent, but connection precision between dies and redistribution layer must be larger
Solution Approach 1:
The patent changes the geometric parameters of the conductors by forming them with oblong cross-sections having enlarged ends. This parameter modification allows the use of pre-fabricated redistribution layers with larger tolerances, as the enlarged ends of the oblong conductors can accommodate the less precise positioning while still achieving reliable connections.
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 approach enables a compromise between reducing internal contact element spacing and increasing the cost-effectiveness of the packaged device by allowing larger spacing and dimensions of connections, facilitating a more efficient use of the active face area without the need for precise masking and plating operations, thus enhancing the packaging efficiency and reducing manufacturing costs.
Implementation Method 1
The conductors are capped by respective elements of fusible material contacting the respective interconnectors, which are then fused by heat or other energy.
Data Source
AI summary
A semiconductor device has external, exposed electrical contacts at an device active face and a semiconductor die, which has internal, electrical contacts at a die active face. The exposed contacts are offset from the internal contacts laterally of the device active face. A redistribution layer includes a layer of insulating material and redistribution interconnectors within the insulating material, the interconnectors connecting with the exposed contacts. A set of conductors connect the internal contacts and the interconnectors. The conductors have oblong, tear drop shaped cross-sections extending laterally of the die active face beyond the respective internal contacts, and contact the interconnectors at positions spaced further apart than the internal contacts. The redistribution layer may be prefabricated using less costly manufacturing techniques such as lamination.