Semiconductor Package Stiffener Layout for Warpage Reduction
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Solution Overview
Problem
Semiconductor packages experience significant warpage during the packaging process, leading to assembly defects such as short circuits, and existing stiffeners with high moduli of elasticity do not effectively reduce warpage, especially in large packages.
Innovation Solution
A semiconductor package design that includes a stiffener with corner parts bonded to the package substrate and leg parts spaced apart from the substrate, featuring bent parts with residual stress to counteract warpage, improving flexural rigidity and reducing package warpage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thick structures with high moduli of elasticity are applied as stiffeners, then flexural rigidity is improved, but the effect of reducing warpage of large semiconductor packages is small
Solution Approach 1:
The stiffener is divided into multiple leg parts (first, second, third, fourth leg parts) that are spaced apart from the package substrate. Each leg part independently contributes to warpage reduction, allowing the stiffener to effectively counteract warpage across large package areas where a single thick structure would be insufficient.
Solution Approach 2:
Instead of increasing thickness (one dimension) to improve rigidity, the invention transitions to a multi-dimensional configuration where leg parts are positioned at different locations and heights above the substrate. This spatial arrangement creates a three-dimensional stiffening structure that provides superior warpage control for large packages without requiring excessive thickness.
2Adaptability or versatility
If semiconductor packages increase in size and decrease in thickness, then application product diversity is improved, but warpage of semiconductor packages is significantly increasing
Solution Approach 1:
The stiffener configuration is specifically designed for large semiconductor packages with particular geometric characteristics. The leg parts are positioned at corners and edges of the package substrate, providing localized stiffening exactly where warpage tends to occur most in large, thin packages, thereby maintaining stability for this specific application class.
Solution Approach 2:
The stiffener is formed as a separate component with different material properties than the package substrate, creating a composite structure. This allows the stiffener to provide the necessary mechanical support and warpage control while the substrate maintains its thin, application-optimized design for diverse semiconductor products.
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 effectively reduces warpage in semiconductor packages of various sizes, enhancing assembly precision and preventing defects like short circuits by applying stress in the opposite direction of warping, thus maintaining the package flat.
Implementation Method 1
featuring bent parts with residual stress to counteract warpage
Data Source
AI summary
A semiconductor package includes a package substrate, a semiconductor chip that is bonded to the package substrate, and a stiffener that is adjacent to the semiconductor chip and is bonded to the package substrate. The stiffener includes a plurality of corner parts that are bonded to a plurality of corner regions of the package substrate, and a plurality of leg parts that are spaced apart from the package substrate. Each of the plurality of leg parts connects corresponding two leg parts of the plurality of leg parts with each other.