Stiffener Design for Semiconductor Package Warpage Control
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Solution Overview
Problem
The miniaturization of semiconductor devices leads to warpage issues due to differences in thermal expansion coefficients among components in a semiconductor package, necessitating a solution to control and prevent warpage.
Innovation Solution
A semiconductor package design incorporating a stiffener with a horizontal and vertical portion, spaced apart from the substrate's side surface, which extends outward and includes adhesive layers to prevent warpage by distributing thermal stress effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple semiconductor chips and devices are mounted in a single package for miniaturization, then device integration is improved, but warpage occurs due to thermal expansion coefficient differences
Solution Approach 1:
The stiffener is positioned at specific locations around the substrate periphery rather than uniformly distributed, targeting areas where warpage stress is most critical. This localized reinforcement approach provides effective warpage control while minimizing additional material usage and maintaining package miniaturization goals.
Solution Approach 2:
The stiffener is constructed from materials with different thermal expansion coefficients than the substrate, creating a composite structure that compensates for thermal stress. This composite approach allows the package to maintain structural integrity across temperature variations while supporting multiple mounted devices.
2Stability of the object's composition
If a stiffener is added to control warpage, then package stability is improved, but device complexity increases
Solution Approach 1:
The stiffener is divided into a body portion and an extended portion, with the extended part projecting beyond the substrate periphery. This segmentation allows the stiffener to provide both internal reinforcement and external anchoring, enhancing warpage control without requiring a completely complex structural redesign.
Solution Approach 2:
The stiffener serves multiple functions: it reinforces the substrate to prevent warpage, provides thermal management support, and acts as a mechanical anchor for the package structure. This multi-functionality reduces the need for separate components, thereby limiting the increase in overall device complexity.
3Stability of the object's composition
If the stiffener outer width is increased to 40 mm or more for better warpage control, then package stability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The stiffener's extended portion projects beyond the substrate periphery, providing excessive reinforcement that compensates for manufacturing tolerances. This design ensures that even with variations in stiffener dimensions, the package maintains adequate warpage control, reducing the stringency of manufacturing precision requirements.
Solution Approach 2:
The stiffener width is set to a specific parameter (40 mm or more) that provides sufficient warpage control while balancing manufacturability. This parameter optimization ensures that the stiffener is wide enough to be effective but not so wide as to create insurmountable manufacturing precision challenges.
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 stiffener effectively reduces and prevents warpage of the semiconductor package by managing thermal expansion and maintaining structural integrity during the package-forming process.
Implementation Method 1
an adhesive layer disposed on an edge of the upper surface of the substrate
Implementation Method 2
Due to the difference in thermal expansion coefficient between various components in a semiconductor package, the semiconductor package may become warped
Data Source
AI summary
A semiconductor package includes a substrate including an upper surface and a side surface, an adhesive layer disposed on an edge of the upper surface of the substrate, and a stiffener including a horizontal portion disposed on the adhesive layer and extending in an horizontal direction to an outside of the substrate in a plan view and a vertical portion connected to the horizontal portion and extending vertically downwards from the horizontal portion. The vertical portion is spaced apart from the side surface of the substrate with a vertical gap extending in a vertical direction therebetween, and the outer width of the stiffener is 40 mm or more.