Face-to-Face MOSFET Package Layout for Thin High-Current Pulses
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Solution Overview
Problem
Standard 'TO' type semiconductor device packages, such as the TO-247 package, are effective but lack the capability to handle short pulses of very high current efficiently, necessitating a design that can manage high transconductance without overheating, which is not adequately addressed by existing thick metal die-attach plugs or tabs.
Innovation Solution
A novel packaged semiconductor device with a thin profile, featuring two face-to-face mounted semiconductor dice and no internal bondwires, utilizing a unique lead configuration where the drain electrodes of the dice are electrically coupled to a third lead, allowing for efficient energy dissipation without the need for thick die-attach plugs or tabs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a standard TO type package with thick metal die-attach plug or tab is used, then thermal management is improved, but the profile thickness increases and high current pulse handling capability is not sufficient
Solution Approach 1:
The invention divides the semiconductor device into two separate dice mounted face-to-face, with each die handling separate current paths. This segmentation allows the package to handle high current pulses through multiple parallel paths while maintaining a thin profile without requiring thick die-attach plugs or tabs.
Solution Approach 2:
Instead of increasing thickness in the vertical dimension to improve thermal management, the invention utilizes the lateral dimension by mounting two dice face-to-face. This dimensional approach allows heat dissipation and current handling to be achieved through parallel lateral arrangement rather than vertical stacking with thick metal attachments.
2Power
If two face-to-face semiconductor dice are mounted in a thin profile package, then high transconductance gain is achieved for high current pulses, but thermal dissipation during continuous operation becomes a concern
Solution Approach 1:
The invention is optimized for periodic pulsed operation rather than continuous operation. The two face-to-face dice can handle short pulses of very high current (one thousand amperes to eight thousand amperes for one microsecond to two hundred microseconds) by distributing the current load, achieving high transconductance gain during these periodic pulses while the thin profile is maintained.
3Temperature
If thick metal die-attach plug or tab is used in TO type package, then thermal conduction is improved, but device complexity and manufacturing complexity increase
Solution Approach 1:
The invention extracts and eliminates the thick metal die-attach plug or tab from the package structure. By using two face-to-face mounted dice with standard bonding, the patent achieves adequate thermal management without requiring the complex thick metal attachment structure, thereby reducing device complexity while maintaining functionality.
4Ease of manufacture
If standard TO type package with single die is used, then manufacturing is simplified, but high current pulse handling capability is insufficient
Solution Approach 1:
The invention merges two semiconductor dice into a single package with face-to-face mounting, allowing the combined structure to handle high current pulses (one thousand amperes to eight thousand amperes) that a single die could not handle alone. This merging approach maintains manufacturing simplicity by using standard bonding techniques while achieving the required power handling capability through the combined parallel operation of two dice.
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 design enables high transconductance performance during short high-current pulses without overheating, achieving a thin profile while accommodating two IGBT or MOSFET dice, thereby improving energy dissipation and reducing thermal management needs.
Implementation Method 1
total energy dissipated in the package can be absorbed by the two semiconductor dice themselves without the devices overheating
Data Source
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AI summary
A packaged semiconductor device has a thin profile, two face-to-face mounted power semiconductor device dice, and no internal bond wires. A first semiconductor device die is mounted so that a gate pad is bonded to the bottom of a first lead, and so that a source pad is bonded to the bottom of a second lead. A second semiconductor device die identical to the first is mounted so that a gate pad is bonded to the top of the first lead, and so that a source pad is bonded to the top of the second lead. The backside drain electrodes of both dice are electrically coupled to a third lead (5). The third lead in one example has a forked-shape, and the two dice are disposed entirely between the two tines of the fork. After encapsulation, the three leads extend parallel to each other from a body portion of the package.