Interconnect Clip With Raised Bridge for Semiconductor Packages
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Solution Overview
Problem
Existing semiconductor packaging technologies face challenges in maximizing the thickness of metal interconnect clips to minimize electrical and thermal resistivity while maintaining a high die to package size ratio, due to constraints such as die size and minimum spacing between the die and clip.
Innovation Solution
The design of an interconnect clip with a bridge portion and die contact portion that have a uniform thickness, allowing the semiconductor die to encroach closer to the package edge, and a lead contact portion with angled surfaces for efficient current conduction, along with a method involving a two-step process of bending and half-cutting to achieve a desired vertical offset and narrow contact interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of metal interconnect clips is increased to minimize electrical and thermal resistivity, then electrical and thermal performance is improved, but the die to package size ratio decreases due to constraints such as die size and minimum spacing between the die and clip
Solution Approach 1:
The interconnect clip employs a non-planar, three-dimensional configuration with a raised bridge portion that elevates the contact surfaces vertically. This dimensional change allows the clip to achieve sufficient thickness for low resistivity while maintaining a compact footprint that preserves the die to package size ratio.
Solution Approach 2:
The clip design modifies the thickness parameter strategically - the bridge portion has increased thickness to minimize electrical and thermal resistivity, while the overall clip dimensions are optimized to maintain the required die to package size ratio. This selective parameter adjustment resolves the contradiction between performance and size efficiency.
2Reliability
If the thickness of the interconnect clip is increased, then electrical and thermal resistivity is reduced, but the package size increases
Solution Approach 1:
The raised bridge portion utilizes the vertical dimension to provide increased thickness for current and heat flow paths without expanding the horizontal package footprint. This allows reduced resistivity while maintaining compact package dimensions.
Solution Approach 2:
The non-planar clip structure nests the thicker bridge portion within the overall clip geometry, allowing the increased thickness to be accommodated within the existing package volume rather than requiring additional space.
3Productivity
If a narrow contact interface is used, then the die to package size ratio is improved, but manufacturing precision requirements increase due to the need for precise vertical offset control
Solution Approach 1:
The raising of the bridge portion is performed as a preliminary manufacturing step before final assembly. This preliminary action establishes the vertical offset and narrow contact interface geometry in advance, making the subsequent assembly process more tolerant and reducing the precision requirements for final positioning.
Solution Approach 2:
The clip is segmented into distinct functional portions - the raised bridge portion and the contact portions - with the bridge portion's vertical elevation established independently. This segmentation allows the narrow contact interface to be manufactured with controlled precision while maintaining the overall die to package size ratio.
Data Source
AI summary
An interconnect clip includes a die contact portion having substantially planar upper and lower surfaces that are parallel to and opposite from one another, a bridge portion adjoining the die contact portion and having substantially planar upper and lower surfaces that are parallel to and opposite from one another, a lead contact portion adjoining the bridge portion and having a lead contact surface or contact point, and a bridge portion adjoining the die contact portion and having substantially planar upper and lower surfaces that are parallel to and opposite from one another. The lower surface of the die contact portion extends along a first plane. The lower surface of the bridge portion extends along a second plane that is completely above the first plane throughout a complete length of the bridge portion. The lead contact surface or contact point is disposed below the first plane.