Stiffening Microstructure for Packaging Substrate Warpage Control
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Solution Overview
Problem
The miniaturization and increased package density of integrated circuit (IC) chips lead to reduced real-estate for thermal management, causing warping issues that can damage the IC chip package by breaking solder joints and terminal connections, reducing the reliability of semiconductor devices.
Innovation Solution
A packaging substrate design with an opening in the chip mounting surface to accommodate a larger stiffening microstructure that extends below the mounting surface, increasing contact area and torsional rigidity without increasing the overall height, and using a bonding agent to secure the microstructure to both the bottom and side walls of the opening for enhanced warpage control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the substrate is thinned to reduce package height, then the overall package size is reduced, but the substrate becomes more susceptible to warping and stress
Solution Approach 1:
The stiffening microstructure extends in the vertical dimension (Z-axis) by protruding from the chip mounting surface, rather than only expanding in the horizontal plane. This allows the substrate to maintain thinness while gaining warping resistance through the elevated stiffening structure that provides structural support in the vertical dimension.
Solution Approach 2:
The stiffening function is segmented from the bulk substrate material and implemented as a discrete microstructure that protrudes from the surface. This segmented approach allows the substrate to remain thin overall while concentrating stiffness where needed at the mounting surface and beneath it.
2Reliability
If a larger stiffening microstructure is used to improve warping resistance, then the contact area increases, but the overall height of the package increases
Solution Approach 1:
Instead of increasing the horizontal footprint of the stiffening microstructure, the solution extends the stiffening structure in the vertical dimension by allowing it to protrude from the chip mounting surface. This provides increased contact area and stiffness without increasing the package's overall height.
3Productivity
If miniaturization is increased to reduce package size, then the real-estate for thermal management is reduced, but the package density is increased
Solution Approach 1:
The stiffening microstructure serves multiple functions simultaneously: it provides mechanical stiffness to prevent warping, acts as a thermal management structure through its conductive material composition, and maintains electrical isolation through the dielectric layer. This multi-functionality allows thermal management capabilities to be integrated into the structural support element rather than requiring separate dedicated thermal structures.
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 design significantly enhances the resistance to warping and maintains planarity, even in thinner substrates, thereby improving the reliability and performance of semiconductor devices by providing greater structural rigidity and thermal management without increasing the footprint.
Implementation Method 1
using a bonding agent to secure the microstructure to both the bottom and side walls of the opening
Data Source
AI summary
A packaging substrate, a packaged semiconductor device, a computing device and methods for forming the same are provided. In one embodiment, a packaging substrate is provided that includes a packaging structure having a chip mounting surface and a bottom surface. The packaging structure has at a plurality of conductive paths formed between the chip mounting surface and the bottom surface. The conductive paths are configured to provide electrical connection between an integrated circuit chip disposed on the chip mounting surface and the bottom surface of the packaging structure. The packaging structure has an opening formed in the chip mounting surface proximate a perimeter of the packaging structure. A stiffening microstructure is disposed in the opening and is coupled to the packaging structure.