Corrugated Semiconductor Leads for High I/O Density
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Solution Overview
Problem
Conventional lead frames for surface mount packaging are limited in accommodating an increasing number of input/output pads on semiconductor dies, as increasing the number of leads either enlarges the package size or shrinks the lead size, which is undesirable.
Innovation Solution
A lead frame with corrugated leads is developed, where each lead frame site has a flag portion and corrugated leads extending from it, allowing multiple wire bonds to connect to I/O pads on the semiconductor die, and the leads are encapsulated and then separated to form individual packages, enabling more I/O connections without increasing package size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of leads around the die is increased to accommodate more I/O pads, then the number of I/O connections is improved, but the package size increases
Solution Approach 1:
The lead frame structure transitions from a conventional planar arrangement to a three-dimensional configuration by adding vertical height through stacked lead frames. Multiple lead frames are stacked vertically with corresponding leads aligned, allowing multiple I/O connections to be achieved within the same footprint area by utilizing the vertical dimension rather than expanding horizontally.
2Quantity of substance
If the number of leads around the die is increased to accommodate more I/O pads, then the number of I/O connections is improved, but the lead size decreases
Solution Approach 1:
Multiple lead frames are stacked and merged vertically, with corresponding leads from each frame aligned and combined. This merging approach allows the system to achieve a high number of I/O connections while each individual lead maintains its original size and structural integrity, as the leads are combined in the vertical dimension rather than being distributed across a larger horizontal area.
Data Source
AI summary
A semiconductor device includes a lead frame site including a die attach region and corrugated metal leads around the die attach region. Each of the corrugated metal leads includes two or more corrugations. Each of the two or more corrugations includes a first flat horizontal portion, a first vertical portion with a first end directly adjacent and connected to a first end of the first flat horizontal portion, a second flat horizontal portion with a first end directly adjacent and connected to a second end of the first vertical portion, and a second vertical portion with a first end directly adjacent and connected to a second end of the second flat horizontal portion. The first flat horizontal portion is in a different plane than the second flat horizontal portion.