Multi-Die Semiconductor Package with Symmetrical Faceup Mounting
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Solution Overview
Problem
The complexity and cost of multi-die semiconductor packaging are increased due to asymmetrical internal wirings and the need for rewiring in conventional methods, where dies on both sides of the lead frame are mounted in different directions, leading to increased package process complexity and costs.
Innovation Solution
A multi-die semiconductor package structure where a first die and a second die are mounted faceup on opposite sides of a die pad with via holes, allowing electrical connection through these holes using bond wires, eliminating the need for rewiring by ensuring symmetrical internal wirings and mirror symmetrical bond pads, using a lead frame made of copper, nickel, or metal alloys with insulated spacer films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If dies are mounted on both sides of the lead frame in different directions to form a multi-die package, then package density is increased, but internal wirings become asymmetrical requiring additional rewiring processes
Solution Approach 1:
The patent applies asymmetry by intentionally designing the die mounting configuration to be symmetrical (both dies faceup) rather than following the conventional asymmetrical approach (dies in different directions). This symmetrical arrangement ensures that internal wirings remain symmetrical, eliminating the need for additional rewiring processes while maintaining high package density.
Solution Approach 2:
The patent inverts the conventional mounting approach by mounting both dies in the same direction (faceup) instead of mounting them in opposite directions. This inversion of the traditional asymmetric mounting method creates a symmetrical wiring configuration that eliminates the need for complex rewiring operations.
2Manufacturing precision
If rewiring is performed on one die to achieve mirror symmetrical bond pads, then electrical connection symmetry is improved, but manufacturing costs increase
Solution Approach 1:
The patent applies preliminary action by pre-configuring both dies to be mounted faceup in the same direction before the bonding process. This preliminary symmetrical arrangement ensures that internal wirings and bond pads are naturally symmetrical, eliminating the need for subsequent rewiring operations and reducing manufacturing costs.
Solution Approach 2:
The patent extracts the unnecessary rewiring step from the manufacturing process by designing a mounting configuration that naturally produces symmetrical bond pads. By removing the problematic asymmetrical mounting approach, the need for additional rewiring operations is eliminated, simplifying the manufacturing process.
3Device complexity
If conventional multi-die packaging is used with asymmetrical wirings, then package structure is simple, but additional rewiring processes are required
Solution Approach 1:
The patent applies asymmetry by intentionally designing the die mounting configuration to be symmetrical (both dies faceup) rather than following the conventional asymmetrical approach (dies in different directions). This symmetrical arrangement ensures that internal wirings remain symmetrical, eliminating the need for additional rewiring processes while maintaining high package density.
Solution Approach 2:
The patent ensures continuity of useful action by creating a seamless manufacturing process where the symmetrical mounting configuration directly produces symmetrical bond pads without interruption for rewiring. This continuous process eliminates idle time and additional processing steps, improving overall package process efficiency.
Data Source
AI summary
The present invention provides a multi-die semiconductor package structure and a manufacturing method thereof, which includes providing at least two dies and a lead frame including a die pad and a lead wire located at the periphery of the die pad, the die pad has a via hole at the edge thereof, binding a base opposite side of a first die to the die pad; electrically connecting the first die to the lead wire through the via hole; binding a base side of a second die to the die pad, the first and second dies are disposed on the opposite sides of the die pad respectively; electrically connecting the second die to the lead wire; stacking other dies above the first or second die and electrically connecting them to the lead wire; and encapsulating said at least two dies and the lead frame to form a package.