Screw-Fixed Semiconductor Stiffener Structure for Warpage Control
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Solution Overview
Problem
Semiconductor packages face reliability issues due to warpage caused by differences in thermal expansion coefficients of components, leading to non-connection problems between solder balls and module substrates.
Innovation Solution
A semiconductor package design that includes a stiffener with a main portion covering the chip structure's upper surface, a vertical portion covering lateral sides, and an edge portion extending to cover the package substrate, with screws penetrating the edge portion and substrate to couple the stiffener, thereby controlling warpage and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional semiconductor package structure is used without additional stiffening components, then the device complexity is low, but warpage occurs due to differences in thermal expansion coefficients leading to non-connection problems
Solution Approach 1:
The stiffener is divided into multiple functional portions: a main portion covering the chip structure, a vertical portion covering lateral sides, and an edge portion extending to the package substrate. This segmentation allows each portion to address specific warpage issues in different regions, improving overall connection reliability while managing structural complexity through functional division
Solution Approach 2:
The stiffener extends in multiple dimensions with the vertical portion rising from the main portion and the edge portion extending laterally to the substrate. This multi-dimensional structure provides comprehensive warpage suppression across different spatial planes, enhancing reliability by addressing warpage from multiple directional perspectives
2Reliability
If the stiffener is designed to fully cover the package substrate with extensive edge portions, then warpage control is improved, but the area occupied by the stiffener increases
Solution Approach 1:
The edge portion of the stiffener is strategically positioned to extend only to specific regions of the package substrate where warpage control is most critical. This localized approach provides effective warpage suppression at key areas without requiring the stiffener to cover the entire substrate area, thus maintaining reliability while minimizing the stiffener's footprint
Data Source
AI summary
A semiconductor package includes a package substrate. A chip structure is on the package substrate. A stiffener covers the chip structure and the package substrate. Screws fix the stiffener to the package substrate. The stiffener includes a main portion that covers an upper surface of the chip structure. A vertical portion that covers lateral side surfaces of the chip structure. The vertical portion extends from an end of the main portion. An edge portion extending laterally from the vertical portion and covering the upper surface of the package substrate. The screws penetrate the edge portion and the package substrate and couple the edge portion to the package substrate.