Multichip Discrete Package With Extended Die Attach Pads
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Solution Overview
Problem
Designing a multiple die package that offers marketing advantages over conventional packages while maintaining high density circuitry and efficient electrical connections is a challenge due to the complexity of integrating multiple circuit elements in a single package.
Innovation Solution
A multichip discrete package design featuring a leadframe with extended die attach pads and wirebonds connecting multiple discrete dies to leads, with a metal plate forming additional attach pads and encapsulating material for structural integrity and electrical connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple discrete dies are integrated in a single package to achieve higher density circuitry, then circuit density is improved, but device complexity increases
Solution Approach 1:
The package is segmented into distinct functional zones: a first die attach pad for mounting discrete dies, a second die attach pad for additional mounting, and a heatspreader region for thermal management. This segmentation allows multiple dies to be integrated systematically while managing complexity through organized spatial distribution of components.
Solution Approach 2:
The metal heatspreader serves multiple functions: it acts as a thermal management component, provides structural support, and functions as a second die attach pad. This multi-functionality reduces the need for separate components, thereby increasing circuit density without proportionally increasing package complexity.
2Ease of manufacture
If extended die attach pads with side portions are used to accommodate multiple dies, then manufacturing flexibility is improved, but metal consumption increases
Solution Approach 1:
The extended side portions of the die attach pads serve dual purposes: they provide additional bonding surface area for accommodating multiple dies with different orientations, and they form integral parts of the heatspreader structure. This eliminates the need for separate metal components, thereby maintaining manufacturing flexibility without excessive metal consumption.
Solution Approach 2:
The die attach pad extensions are merged with the heatspreader structure, creating a unified metal component that performs both attachment and thermal management functions. This consolidation reduces the total metal content compared to using separate components for each function.
3Reliability
If wirebonds are used to form electrical connections between dies and leads, then electrical connectivity is improved, but manufacturing complexity increases
Solution Approach 1:
The electrical connection system is segmented into discrete wirebond pathways, each independently routed from specific die bonding pads to corresponding leads. This segmentation allows for standardized wirebonding procedures to be applied systematically, improving reliability while managing manufacturing complexity through modular connection patterns.
4Strength
If encapsulating material is formed around multiple dies and DAPs, then structural integrity is improved, but manufacturing steps increase
Solution Approach 1:
The encapsulation process is merged with the molding operation that also forms the heatspreader structure. By combining these manufacturing steps into a single molding operation, structural integrity is achieved without proportionally increasing the number of manufacturing steps.
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
The solution enables a compact, high-density circuit assembly with efficient electrical connections, suitable for applications like differential amplifiers and dual MOSFET stages, while using approximately the same amount of metal as conventional packages, thus offering competitive market advantages.
Implementation Method 1
a metal plate attached to tops of the side portions forming a second DAP
Implementation Method 2
at least a first wirebond which forms an electrical connections between the first discrete die and a first selected one of the plurality of leads
Implementation Method 3
encapsulating material formed around the first and second die and the first and second DAPs
Data Source
AI summary
A multichip discrete package with a leadframe having a plurality of leads and a first die attach pad (DAP), the first DAP having side portions that extend above the first DAP, a first discrete die bonded to the first DAP, at least a first wirebond which forms an electrical connections between the first discrete die and a first selected one of the plurality of leads, a metal plate attached to tops of the side portions forming a second DAP, a second discrete die bonded to the second DAP, at least a second wirebond which forms an electrical connections between the second discrete die and a second selected one of the leads; and encapsulating material formed around the first and second die and the first and second DAPs.