Leadframe Interconnect for Transistor Arrays
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Solution Overview
Problem
Conventional switch circuits requiring multiple transistors connected in parallel face complexity and manufacturing challenges due to intricate metal interconnects, leading to potential failure and low yields, as well as insufficient impedance paths.
Innovation Solution
A leadframe device with conductive paths provides electrical connectivity between isolated transistor nodes, eliminating the need for on-chip metal interconnects and enabling scalable, low-impedance connections through a centralized driver circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple transistors are connected in parallel via on-chip metal interconnects, then high current drive and low impedance switching capability are achieved, but device complexity and manufacturing difficulty increase significantly
Solution Approach 1:
The patent extracts the interconnect function from the chip itself and relocates it to the substrate level. Individual transistor nodes are connected to the substrate through bump bonds, and the parallel connection of multiple transistors is achieved through substrate-level routing rather than complex on-chip metal interconnects. This reduces on-chip complexity while maintaining the parallel transistor functionality.
Solution Approach 2:
The patent moves the interconnection from the two-dimensional on-chip plane to the three-dimensional substrate level. By using bump bonds to connect chip nodes to substrate pads and then routing through the substrate, the interconnect structure utilizes the vertical dimension and substrate volume, thereby simplifying the on-chip metal layer complexity.
2Power
If multiple transistors are connected in parallel via on-chip metal interconnects, then low impedance switching path is achieved, but manufacturing yield decreases due to potential failure points
Solution Approach 1:
The patent extracts the low-impedance interconnect function from the on-chip metal layers and implements it through the substrate using copper traces and via holes. This separates the sensitive on-chip transistor fabrication from the robust substrate-level interconnect fabrication, allowing each to be optimized independently and reducing the propagation of manufacturing defects.
Solution Approach 2:
The substrate acts as an intermediary between the chip nodes and the external connections. The bump bonds serve as intermediaries that connect the chip fabrication process to the substrate interconnect process, isolating the chip from substrate-level manufacturing variations and reducing the impact of substrate fabrication defects on overall yield.
3Area of moving object
If conventional surface mount technology is used with leads or small leads, then device size is reduced, but electrical connectivity and current handling capability are limited
Solution Approach 1:
The patent utilizes the substrate as a third dimension for current handling and connectivity. Instead of relying on planar lead structures, the current paths extend through the substrate volume via copper traces and via holes, providing low-impedance paths without increasing the device footprint. The substrate acts as a volumetric interconnect medium rather than a planar connector.
Solution Approach 2:
The substrate serves multiple functions simultaneously: it provides mechanical support, electrical interconnection, heat dissipation, and current handling capability. The copper traces and via holes in the substrate provide robust electrical connectivity for high current applications while maintaining a compact form factor, eliminating the need for large external leads.
Data Source
AI summary
According to example configurations herein, an apparatus comprises a die and a host substrate. The die can include a first transistor and a second transistor. A surface of the die includes multiple conductive elements disposed thereon. The multiple conductive elements on the surface are electrically coupled to respective nodes of the first transistor and the second transistor. Prior to assembly, the first transistor and second transistor are electrically isolated from each other. During assembly, the surface of the die including the respective conductive elements is mounted on a facing of the host substrate. Accordingly, a die including multiple independent transistors can be flipped and mounted to a respective host substrate such as printed circuit board, lead frame, etc.