Combined Lead and Clip Frame Package for Compact Power Modules
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Solution Overview
Problem
Existing power modules, such as integrated power modules (IPMs), are costly and require expensive substrates like DBC or AMB, and there is a need for a more reliable and cost-effective semiconductor package design.
Innovation Solution
A semiconductor package design utilizing a combined lead frame and clip frame structure that accommodates two semiconductor dies, allowing for electrical interconnection and reduced package footprint, using a molded package design with a first lead frame for die attachment and a second lead frame for vertical offset contacts, and a clip section for connecting the second die, reducing reliance on expensive substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If expensive substrates like DBC or AMB are used for power modules, then reliability and performance are improved, but manufacturing cost increases significantly
Solution Approach 1:
The patent replaces expensive DBC/AMB substrates with a cost-effective lead frame structure that uses standard PCB mounting techniques. The lead frame serves as a disposable, low-cost substrate that achieves adequate reliability for the application without requiring expensive specialized substrates.
Solution Approach 2:
The patent extracts the essential function of the expensive DBC/AMB substrate (electrical connection and mechanical support) and implements it separately using a lead frame attached to a standard PCB. This separation allows the use of inexpensive components to achieve the same functional outcome.
2Adaptability or versatility
If multiple semiconductor dies are mounted on expensive substrates, then functional integration is improved, but package complexity and cost increase
Solution Approach 1:
The patent combines multiple semiconductor dies (rectifier diodes, transistors, control logic) onto a single lead frame structure that is then mounted on a standard PCB. This merging approach integrates multiple functions into one package while using simple, standard components rather than complex specialized substrates.
Solution Approach 2:
The lead frame serves multiple functions simultaneously: it provides mechanical support for multiple semiconductor dies, establishes electrical connections between dies and the PCB, and enables standard PCB mounting techniques. This multi-functionality reduces the need for specialized complex substrates.
3Ease of manufacture
If traditional separate mounting of semiconductor dies is used, then manufacturing simplicity is maintained, but package footprint and congestion increase
Solution Approach 1:
The patent nests multiple semiconductor dies within the lead frame structure, arranging them in a compact configuration where dies are mounted close together on the lead frame before attachment to the PCB. This nesting approach reduces the overall package footprint while maintaining manufacturability.
Data Source
AI summary
A method of forming a semiconductor package includes providing a first lead frame that comprises a die attach region with a plurality of first contacts and a first clip section that is attached to one or more of the first contacts, performing a first die attach step that mounts a first semiconductor die within the die attach region of the first lead frame, electrically connecting terminals of the first semiconductor die with at least some of the first contacts, providing a second lead frame that includes a die pad and a plurality of second contacts that are attached to the die pad and are vertically offset from the die pad, performing a second die attach step that mounts a second semiconductor die on the die pad, and performing a clip attach step that affixes an upper surface of the second semiconductor die to the first clip section.