Interdigitated Cantilever Lead Frame for Smaller Chip-on-Lead Packages
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing chip-on-lead semiconductor packages face challenges in achieving a smaller footprint and reliable electrical connections due to the exposure of leads at the bottom surface, which limits the placement on circuit substrates and increases package area.
Innovation Solution
A semiconductor package design featuring cantilevered and interdigitated leads that extend from opposite sides of the package, with electrical connections formed over these leads, allowing for a smaller footprint and improved support during connection formation, using a chip-on-lead configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If leads are exposed at the bottom surface under the semiconductor die, then electrical connections can be made, but the package area increases and placement on circuit substrates is limited
Solution Approach 1:
The leads are configured to extend from opposite sides of the package and interdigitate underneath the die, moving the electrical connection interface from the bottom surface to the sides of the package. This dimensional repositioning reduces the footprint while maintaining connection functionality.
Solution Approach 2:
The leads are nested underneath the semiconductor die in an interdigitated configuration, with first leads extending under second leads. This nesting arrangement allows electrical connections to be made without exposing leads at the bottom surface, thereby reducing package area while maintaining connectivity.
2Reliability
If leads extend past each other under the die, then support during connection formation is improved, but manufacturing complexity increases
Solution Approach 1:
The lead structure is segmented into first leads and second leads that are interleaved in an alternating pattern underneath the die. This segmentation provides distributed support points during connection formation while maintaining a systematic, manufacturable configuration.
Solution Approach 2:
The first leads and second leads are positioned asymmetrically with respect to each other in an interdigitated pattern, with first leads extending further in one direction and second leads extending further in the opposite direction. This asymmetric arrangement optimizes support during connection formation while remaining compatible with standard manufacturing processes.
Data Source
AI summary
A semiconductor package has a chip-on-lead configuration with leads that are cantilevered and interdigitated. The leads extend from contact surfaces on opposite sides of the semiconductor package to support locations under a semiconductor die that is attached to the leads. The contact surfaces are exposed at a bottom surface of the semiconductor package, adjacent to a perimeter of the semiconductor package. The leads from opposite sides of the semiconductor package extend past each other under the die. The cantilevered leads do not extend to the bottom surface under the semiconductor die. The semiconductor package includes electrical connections from the semiconductor die to the leads. The semiconductor package is formed by attaching the semiconductor die to the leads, followed by forming the electrical connections.