Semiconductor Package Thermal Interface Structure for Stress Relief
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Solution Overview
Problem
Conventional semiconductor packages experience high thermal-mechanical stress, leading to silicon cracking, which is mitigated by additional backside metallization, but this approach is not always necessary with the proposed thermal interface structures that reduce stress without additional metallization.
Innovation Solution
A semiconductor package design incorporating a metallic thermal interface structure between semiconductor devices and a cover, utilizing high thermal conductivity materials like gallium-based solders and a spacer to efficiently transfer heat while minimizing stress, thereby eliminating the need for additional backside metallization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional backside metallization is used to reduce thermal-mechanical stress, then reliability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts and eliminates the unnecessary backside metallization layer from the conventional package structure. By using a metallic thermal interface structure with high thermal conductivity and appropriate mechanical properties, the invention removes the additional metallization step while maintaining stress reduction functionality, thereby simplifying device structure and reducing manufacturing complexity
Solution Approach 2:
The metallic thermal interface structure serves as an intermediary between the semiconductor device and the heat sink. This intermediate layer not only provides thermal conduction but also acts as a stress buffer due to its mechanical properties, replacing the need for backside metallization that previously served as a stress relief mechanism
2Ease of manufacture
If conventional packaging is used, then manufacturing is simpler, but thermal-mechanical stress causes silicon cracking reducing reliability
Solution Approach 1:
The patent changes the thermal and mechanical parameters of the interface between semiconductor device and heat sink by introducing a metallic thermal interface structure. This structure has high thermal conductivity to improve heat dissipation and appropriate mechanical compliance to reduce thermal-mechanical stress, thereby enhancing reliability without significantly complicating the manufacturing process
3Temperature
If high thermal conductivity materials are used in thermal interface structure, then heat dissipation is improved, but manufacturing complexity increases
Solution Approach 1:
The metallic thermal interface structure employs composite material design, combining high thermal conductivity materials with appropriate mechanical properties. This composite approach enables simultaneous achievement of effective heat dissipation and stress reduction, while the integrated structure design keeps the manufacturing process manageable without requiring excessively complex fabrication steps
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 solution effectively reduces thermal-mechanical stress on semiconductor packages, enhancing heat dissipation capabilities and preventing silicon cracking without requiring additional backside metallization, thus improving the reliability and performance of the packages.
Implementation Method 1
utilizing high thermal conductivity materials like gallium-based solders and a spacer to efficiently transfer heat
Data Source
AI summary
A semiconductor package includes a package substrate; semiconductor devices disposed on the package substrate; a package ring disposed on a perimeter of the package substrate surrounding the semiconductor devices; a cover including silicon bonded to the package ring and covering the semiconductor devices; and a thermal interface structure (TIS) thermally connecting the semiconductor devices to the cover.